Avraham's Guests – Angels or Men/2

Avraham's Guests – Angels or Men?

Exegetical Approaches

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Angels

The guests who came to Avraham were three angels. This position subdivides regarding the relationship between the angel's visit and Hashem's revelation to Avraham in 18:1:

One Event

Hashem appeared to Avraham via the three angels who came to him.

Sources: JubileesChapter 16:1-11,20-23About Jubilees, PhiloOn Abraham XXII-XXIIIAbout Philo, Kirkisani the Karaite, RashbamBereshit 18:1,13,14,16,20,26Bereshit 19:24About R. Shemuel b. Meir, ShadalBereshit 18:1,3,9,13,17,20,22Bereshit 19:17,18About R. S.D. Luzzatto, Hoil Moshe, R. D"Z HoffmannBereshit 18:1-19:38,18:1-2,3-8,6-8,13-14,20-21Bereshit 19:1-3,18-20About R. D"Z Hoffmann

Hashem's revelation - "'וַיֵּרָא אֵלָיו ה" – According to this position, the first verse of the chapter is a general introduction to the story, and the rest of the chapter provides the details (‎‎כלל ופרט).‎¹  Thus, the unit opens by sharing that Hashem revealed Himself, and then explains how this revelation took place - via the three angels who visited Avraham.²  As such, there is no missing speech of Hashem; the whole chapter constitutes the revelation.

Why isn't Avraham mentioned by name? Since this position views verse 1 as beginning a new unit,³ it is difficult why Avraham is referred to by a pronoun (connoting a continuation)  and not by his name.  R. D"Z Hoffmann suggests that this teaches that the story is integrally related to the preceding one regarding Avraham's circumcision.  Due to the covenant, Avraham achieved a new level of closeness to Hashem, meriting a visit by angels who could behave as his guests and share with him Hashem's plans.

Calling the angels "Hashem" – According to this approach, the Torah often refers to angels by the name of Hashem, since they are His messengers doing His bidding (‎שלוחו של אדם כמותו).‎⁴ Thus, these sources posit that throughout the chapters, many of the places where Hashem's name appears refers not to Hashem, but to one (or all) of the angels.⁵ See next points for examples.

שם אדנות – Verses 18:3 and 19:18

• "אֲדֹנָי אִם נָא מָצָאתִי חֵן בְּעֵינֶיךָ" – According to Philo, Shadal, and R. D"Z Hoffmann the term "אֲדֹנָי" refers to the angels.⁶ To explain the switch between this plural form and the singular form used in the rest of the verse, R. D"Z Hoffmann suggests that really Avraham was speaking only to the most important of the guests, but out of honor, originally addressed him using the majestic plural.⁷ Kirkisani the Karaite suggests that it is "the way of the text" to use either the singular or the plural when speaking of a group.⁸
• "אַל נָא אֲדֹנָי" – Shadal assumes that here, too, Lot is addressing the angels. R. D"Z Hoffmann brings this as an options but appears to prefer the possibility that this is a prayer of Lot to Hashem.⁹

שם הויה – Verses 18:1, 13, 17, 20, 22, 26 ff – Rashbam¹⁰ is consistent in reading all occurrences of "Hashem" in the chapters as referring to the angels. Only where the angels themselves refer back to Hashem in their own speech (in 18:14 and the second occurrence in 19:24) does he say that the word refers to Hashem Himself.¹¹ This reading has several advantages:

• It easily explains how Sarah heard the rebuke regarding her laughter and why she dared deny it.
• The language of 18:10 and 18:14 is extremely similar since the same person is saying both statements, and simply reinforcing his earlier words.
• According to this reading, Hashem does not constantly interrupt Avraham's interaction with the angels; it is only they who speak throughout.
• Even though Avraham had been accompanying the angels, the verse can still say "וְאַבְרָהָם עוֹדֶנּוּ עֹמֵד לִפְנֵי ה'" since all this implies is that he continued to talk to the third angel after the others left.
• Only two angels arrive by Lot, because the third remained with Avraham while he prayed for Sedom.
• There is no contradiction between the angels saying they will destroy Sedom and 19:24 which has Hashem destroy it, since Rashbam understands Hashem of that verse to refer to the angel Gavriel.

Purpose of the vision=visit – According to Shadal and Hoil Moshe, the main goal of the visit was to tell Avraham about the upcoming destruction of Sedom, and not about the birth of Yitzchak.¹² They point out that there was no reason to repeat news of the birth,¹³ and the angels only mentioned it tangentially in response to the fact that Sarah was sitting alone in her tent, presumably lamenting her barrenness.

Why are the guests referred to as both people and angels? This approach works well with the verses which call the guests angels, but needs to explain those which call them people. Philo suggests that they were so called because they took the form of people,¹⁴ but he does not account for the switch in titles.

Angelic or human actions – This approach easily explains how the guests knew that Sarah was to give birth and how they could blind the people of Sedom or destroy the city¹⁵ but has difficulty explaining the angels' seemingly corporeal actions. Philo explains that the angels simply pretended to eat and drink.¹⁶ Hoil Moshe, though, asserts that despite being angels, they were able to eat while in human form.¹⁷

Did Avraham recognize them as angels?

• Immediately– Hoil Moshe explains the term "נִצָּבִים עָלָיו" to mean that the angels suddenly materialized before Avraham, leading Avraham to realize immediately with whom he was dealing.  He suggests that it is for this reason that Avraham treated them with such respect.¹⁸
• Midway – R. D"Z Hoffmann argues that at first Avraham must not have realized that the guests were angels or he would not have offered them food.¹⁹  He suggests that it is only after the angels chastise Sarah for her doubt that Avraham begins to realize that the beings before him are not normal passers-by.²⁰ 

Why three guests? As Shadal and Hoil Moshe assume that the main job of the angels was to tell Avraham about Sedom, it would seem that one angel would have sufficed.  Hoil Moshe suggests that there was in fact one main angel, but he was accompanied by two lesser servants.  Most of these sources explain that only two arrive by Lot, since the main one was detained when Avraham spoke to him about saving the city.

Beliefs about angels

Distinct Events

Hashem's revelation to Avraham was distinct from the visit of the three angels.

Sources: Justin Martyr in Dialogue with Trypho56-57About Dialogue with Trypho, R. Saadia GaonCommentary Bereshit 18:2,8,17-33Tafsir Bereshit 18:33Tafsir Bereshit 19:18HaNivchar BaEmunot UvaDeiot 2:6About R. Saadia Gaon, RashiBereshit 18:1,2,3,8,16,22,33Bereshit 19:1,18Shevuot 35bAbout R. Shelomo Yitzchaki, RambanBereshit 18:1,3,6,15,20Bereshit 19:24About R. Moshe Nachmanides, Akeidat YitzchakBereshit #19About R. Yitzchak Arama, AbarbanelBereshit 18:1,2,4,9,16,22About R. Yitzchak Abarbanel, Seforno  Bereshit 18:1,2,3,9,12,14,20,22,33Bereshit 19:27About R. Ovadyah Seforno,

Hashem's revelation - "'וַיֵּרָא אֵלָיו ה" – According to all these sources, Hashem's revelation to Avraham was distinct from the visit of the three angels.  They differ, though, regarding its purpose and how they explain why the text does not share the content of Hashem's speech:

• Connected to Chapter 17– Rashi, Ramban and Seforno all suggest that the revelation is connected to Avraham's circumcision in Chapter 17. ²¹ Rashi²² maintains that Hashem appeared to Avraham to visit him as he recuperated,²³ while Ramban asserts that the revelation was simply a sign of honor,²⁴ a reward to Avraham for having fulfilled Hashem's commandment.  Finally, Seforno posits that Hashem appeared so as to take His part in the covenant of circumcision.²⁵ According to all these, there was no need for speech as the revelation was a goal in and of itself.
• Connected to news of Sedom – Both R. Saadia and Abarbanel assert that Hashem's appearance here is connected to His later announcement to Avraham regarding the destruction of Sedom.²⁶ R. Saadia suggests that Hashem appeared before the arrival of the angels, even though he was only to speak later, so that Avraham would feel Hashem's presence as the angels arrived and thereby recognize them as celestial beings.²⁷

Why isn't Avraham mentioned by name? According to Rashi, Ramban and Seforno, who posit that verse 1 is a continuation of the events of Chapter 17, referring to Avraham by a pronoun is not problematic since he was the subject of the previous events.²⁸  They, do however, need to explain why the text provides a setting (time and location) for the event as if it is a new story.²⁹

Did Hashem stay?

• No - According to Rashi, Ramban, and Seforno, it would seem that Hashem left after His visit and that there is no connection at all between His initial revelation and the rest of the chapter.³⁰
• Yes - According to R. Saadia and Abarbanel, Hashem's presence stayed with Avraham throughout the visit of the angels.³¹ Abarbanel asserts that this explains both how Hashem continuously speaks to Avraham while he interacts with his guests (verses 13 and 20) and how the verse later states that "Avraham was still standing before Hashem."³² 

Calling the angels by the name of Hashem - שם הוייה – According to this approach, which distinguishes between Hashem's revelation and the angels' visit,  the name Hashem throughout the chapter refers to Hashem and not the angels.  Thus, it is Hashem who is speaking or referred to in 18:1,13-14,17, 20, 22, 26ff.

Calling the angels by the name of Hashem - שם אדנות – This approach offers two understandings regarding to whom Avraham was speaking when he said, "אֲדֹנָי אִם נָא מָצָאתִי חֵן בְּעֵינֶיךָ":

• Angels – According to all these sources, in these words Avraham was addressing the angels.³³ Ramban and Abarbanel explain that Avraham referred to them by the sacred term "אֲדֹנָי" because he recognized that they were angels.³⁴ R. Saadia, instead, asserts that Avraham assumed that the angels were prophets and meant, "‎איש האלהים"‎³⁵ but spoke in short, skipping the word "‎איש".‎³⁶  This position must explain the switch from plural (אֲדֹנָי), to singular (אַל נָא תַעֲבֹר) and then back to plural in verse 4 (רַחֲצוּ רַגְלֵיכֶם).  Rashi and Seforno³⁷ assert that originally, Avraham was only speaking to the leader, while Ramban³⁸ suggests that Avraham addressed all in the plural, but then asked each one individually to stay.³⁹ Afterwards he offered hospitality to all as a group.⁴⁰
• Hashem – Both Rashi and Abarbanel bring a second opinion, following R. Elazar in Bavli ShabbatShabbat 127aAbout Bavli Shabbat, that Avraham was addressing Hashem,⁴¹ asking Him not to leave despite the guests' appearance.⁴² This reading easily explains the switch between singular and plural language, since there is a change in addressee from Hashem to the angels.

Purpose of the angel's visit – According to this approach, the angel's visit is distinct from Hashem's desire to share the fate of Sedom with Avraham, and was instead aimed at telling Sarah⁴³ about the impending birth of Yitzchak.  Rashi further suggests that Hashem only sent the angels to Avraham because he desired to host guests, while Ramban views the visit as part of Avraham's reward for his circumcision.

Number of Angels – According to Rashi, each of the angels had a different task, one to announce the birth of Yitzchak, one to destroy Sedom, and one to cure Avraham and save Lot.  After the first angel completed its task, it left, leaving two to continue to Sedom.⁴⁴

Why are the guests referred to as both people and angels? The commentators offer several possibilities:

• Interchangeable terms - R. Saadia asserts that the terms are used interchangeably in many places in Tanakh so one need not question the usage here.⁴⁵
• Differing perspective – According to Rashi, since Avraham was used to visiting angels, they were not particularly unique and are called simply "men". However, by Lot, who was not used to them, they are called angels.⁴⁶
• Presence of Hashem - Rashi raises a second possibility, that when Hashem accompanies the angels they are called people (in comparison to Him), but when His presence is lacking they are called angels. This, though, begs the question of why Hashem was with the angels in certain parts of the story and not in others.
• Action-based - According to Abarbanel the angels are called men when they behave like humans and angels when they do godly acts.⁴⁷

Angelic or human actions – The supernatural abilities of the guests is easily explained by their being angels.  These sources differ, though in how they explain their eating:

• Pretense - Rashi and Ramban, following Bereshit Rabbah48:14About Bereshit Rabbah, suggest that they simply pretended to eat.⁴⁸
• Consumption by fire – R. Saadia suggests that the root "אכל" is not limited in meaning to eating by mouth and can also connote other forms of consumption, such as eating by fire or sword.⁴⁹ Thus, here the angels might have burned their food.
• Others ate – R. Saadia also suggests that the verb "וַיֹּאכֵלוּ" referred to all those assembled who ate (Avraham and his servants) but not to the angels.

Did Avraham recognize them as angels?

• Yes – According to Ramban and Abarbanel, Avraham recognized that he was dealing with angels.
• No – According to R. Saadia, despite Hashem hinting to him, Avraham mistook the angels for prophets.⁵⁰

Sarah's laughter – Ramban⁵¹ asserts that Sarah was unaware that the men were angels and thus laughed at their announcement.  She did not hear Hashem's rebuke (since Hashem spoke just to Avraham) but Avraham himself chastised her, leading to her denial. As such, Sarah was not trying to cover up her actions before Hashem, only before her husband.⁵²

"'וְאַבְרָהָם עוֹדֶנּוּ עֹמֵד לִפְנֵי ה" – This verse is not problematic for R. Saadia and Abarbanel who suggest that Hashem's presence had never left Avraham after the initial revelation. According to the others, though, Avraham was not standing before Hashem at this point of the story:

• תיקון סופרים – Rashi asserts that the verse should really read, "וה' עודנו עומד לפני אברהם" since Hashem had just come to speak to Avraham about Sedom (in verse 20) as he accompanied the guests. The text was reversed, though, so as not to dishonor Hashem.
• Until the angel's arrival in Sedom – According to Ramban the phrase is related to the immediately preceding term, "וַיֵּלְכוּ סְדֹמָה"  and comes to explain that Avraham stood before Hashem to plead for Sedom during the entire time that it took the angels to travel there.

Beliefs about angels

People

The three guests were human prophets.  Their discussion with Avraham was distinct from Hashem's revelation in 18:1.

Sources: Opinion brought by Ibn EzraBereshit 18:1,13,33Bereshit 19:2,12,18About R. Avraham ibn Ezra, R. Yosef Bekhor ShorBereshit 18:1,2-4,9,17-19Bereshit 19:1,18-19About R. Yosef Bekhor Shor, RalbagBeiur HaMilot Bereshit 18:2,3,13Beiur HaMilot Bereshit 19:13Beiur Divrei HaParashah Bereshit 18:1,2-8,9-10,13-14,16,17-19,20-21,22,33Beiur Divrei HaParashah Bereshit 19:27-28,37-38About R. Levi b. Gershom

Hashem's revelation - "'וַיֵּרָא אֵלָיו ה" – According to R"Y Bekhor Shor and Ralbag, Hashem's revelation in 18:1 refers to Hashem's later words regarding the destruction of Sedom (18:17 and 20ff). The verse is out of order,⁵³ and in reality the story of the angels in 18:2-16 preceded the revelation. Ralbag suggests that the story of the visit is simply a parenthetical aside, placed here because the guests were enroute to destroy Sedom, which was the very matter which Hashem wanted to discuss with Avraham.⁵⁴

Why isn't Avraham mentioned by name? This approach does not explain why Avraham is not referred to by his name until 18:6.

Purpose of the visit – The prophets came to tell Sarah about the birth of Yitzchak.  Ralbag posits that Avraham's words, "סַעֲדוּ לִבְּכֶם... כִּי עַל כֵּן עֲבַרְתֶּם עַל עַבְדְּכֶם", suggest that the visitors had actually detoured from their path just so that they could eat with Avraham.⁵⁵

Why are the guests referred to as both people and angels? As this approach maintains that the guests were human, it is understandable why they are referred to as "men" in the vast majority of verses, but unclear how they can be called angels. R"Y Bekhor Shor responds that the word "מַּלְאָכִים" does not necessarily refer to celestial beings but simply means messengers.⁵⁶ Ralbag attempts to explain why they are  so-called only when interacting with Lot and not by Avraham,  by suggesting that prophets are only called "‎מַּלְאָכִים" if they are greater prophets than the person to whom they are prophesying.⁵⁷

"אֲדֹנָי אִם נָא מָצָאתִי חֵן בְּעֵינֶיךָ"

• According to R"Y Bekhor Shor the term "אֲדֹנָ" here refers to Hashem.  Upon seeing the guests, Avraham offered up a prayer to Hashem that the group⁵⁸ won't pass by him without stopping. This reading easily explains the switch to plural in the following verse, since only then does Avraham turn to the threesome.
• Ralbag, in contrast, asserts that the word "אֲדֹנָ" refers to the guests, and means "my masters".  He follows R. Chiya in  Bereshit Rabbah48:10About Bereshit Rabbah in explaining that Avraham initially spoke to the leader specifically (thus the singular "תַעֲבֹר") and only afterwards to the group (thus the plural in verse 4).⁵⁹

"וַיֹּאמֶר לוֹט אֲלֵהֶם אַל נָא אֲדֹנָי" – Both Ralbag and R"Y Bekhor Shor maintain that the word "אֲדֹנָי" in this verse refers to the guests. This works with the beginning of the verse which states that Lot said to "them..."⁶⁰

The name of Hashem – According to this approach, throughout the chapter the name Hashem refers to Hashem Himself and not the guests.   Ralbag posits one possible exception, suggesting that 18:13 (לָמָּה זֶּה צָחֲקָה שָׂרָה) might be a guest speaking via prophecy.⁶¹ He is referred to as Hashem after the One who sent him.⁶²

Angelic or human actions – R"Y Bekhor Shor asserts that the fact that the people ate and slept proves that they cannot be angels.⁶³  Their seemingly supernatural actions (foreknowledge that Sarah was to give birth, blinding the people of Sedom etc.) are explained by their prophetic status.⁶⁴

Prophet visting a  prophet? Abarbanel questions this whole approach, asserting that the visitors could not have been prophets because Avraham was the sole prophet of the time.  And even if there were others,⁶⁵ they were definitely not greater than Avraham, so what would be the point of their sharing news with him?⁶⁶  He further questions how they could attribute the destruction of Sedom/saving of Lot to themselves as this is something which was purely in the hands of Hashem.⁶⁷

Beliefs about angels

Motivations – R"Y Bekhor Shor says explicitly his explanation is an answer to the Christians who claim the three guests were three parts of god, therefore he does not take the approach they were angels because that is close to their read.

How many guests – Ralbag says the one who told Avraham he will have a child did not go to Sedom, and this proves how little these prophets prophesied because they were only told one thing.

Crux of the position

Divine Prophecy

All of chapter 18 was a Divine prophecy and the guests that visited Avraham did so only in this vision.

Sources: RambamMoreh Nevukhim 2:42Moreh Nevukhim 2:45About R. Moshe Maimonides, RadakBereshit 18:1,2,3,4,10,12,13,17,22,33Bereshit 19:1,2,3,11,15,16,18,24About R. David Kimchi, R. Yosef ibn KaspiTirat Kesef 2:3Bereshit 18:3,11Bereshit 19:1About R. Yosef ibn Kaspi, AbarbanelCommentary on Moreh Nevukhim 2:42About Abarbanel

Vision and guests – These commentators say that the content of Hashem's revelation in 18:1 is not missing, since the entire chapter and maybe even 19 is the prophecy that Avraham received.⁶⁸ According to this approach, 18:1 is related to what comes after it and not what came beforehand.⁶⁹ Ralbag the Torah does not say explicitly the whole chapter was in a vision.

Purpose of vision = visit – Radak says the purpose was to tell Avraham about Sedom,⁷⁰ and even though Hashem already told Avraham in chapter 17 he will have a child he repeated it here to emphasize and so Sarah will hear. Ramban questions the Torah's need to tell us Sarah baked cakes, laughed, and Avraham made meat if it was all in a vision, and Radak and Abarbanel answer the story teaches us to act kindly like Avraham did.

How are the guests referred to – Rambam says Avraham saw angels often and was not surprised to see them therefore they are called people, but Lot did not see them too often so they are called angels by him. Abarbanel asks that they are only called angels twice by Lot and people more often. Radak says the guests are called people when they act in ways people act, and angels when they act in ways angels act.⁷¹

Is "Hashem", Hashem or the guests

• שם אדנות – Radak⁷² explains both 18:3 and 19:18 to refer to one of the guests.⁷³
• שם הויה – Radak says 18:10, 13 and the first Hashem in 19:24 are talking about the angels, while 18:1 and 17 are talking about Hashem.

Angelic or human actions – According to this approach the guests did not eat nor blind the people of Sedom, rather it was all what Avraham saw in his prophecy.⁷⁴ Did Avraham see angels or people in the vision?

End of prophecy – One would need to assume the people who came to Lot since they are the same people who came to Avraham, in reality did not come, and Lot saw them only in a prophecy just like Avraham. But how could Lot and the people of Sedom⁷⁵ have prophesied? Where did the prophecy end?

• After the end of chapter 18⁷⁶ – Radak.⁷⁷ 18:33 which says Hashem left is talking about the end of the prophecy. According to Radak, Sedom was really destroyed which makes sense from later verses in Torah which mention the destruction of Sedom,⁷⁸ but he does not explain where the guests in chapter 19 came from.
• Avraham prophesied chapters 18-19 – Abarbanel. According to Abarbanel, Sedom was destroyed and Lot was saved but not by angels rather Hashem burnt the cities and brought winds which caused Lot to leave. Abarbanel explains 18:33 which seems to end a vision that Avraham in the verse thought the prophecy ended but it did not.⁷⁹ He explains the repetition between 19:27-28 and 29, that the first two verses were in the prophecy, and 29 is explaining how Lot was saved in reality, and verse 30 he notes makes sense that Lot was afraid to stay in Tzoar because only in Avraham's prophecy did Lot know Tzoar was saved.
• Lot prophesied chapter 19 – Ibn Kaspi. He also understands 18:33 as the end of Avraham's prophecy, but he says Lot had a similar prophecy just he saw only two guests. Ibn Kaspi says Sedom was destroyed besides from in Lot's prophecy. Ibn Kaspi is assuming Lot can have a prophecy, which Rambam and Ralbag do not agree with.⁸⁰ Ralbag also asks how then the people of Sedom talked if it was all in a prophecy, and Ibn Kaspi probably answers like he says about Sarah, that Lot in his prophecy heard the people of Sedom talking to him.

Sarah prophesied – Radak brings a parallel to Daniel 11:7 where the people in the room with Daniel also felt something even though just Daniel was prophesying, and he says that was the case by Sarah which heard something even though just Avraham was prophesying. Sarah did not know he was an angel rather thought he was a prophet and that is why she laughed. Ralbag is not convinced and says Sarah could not have heard Avraham's prophecy, and if she prophesied herself she would not laugh at it. Ibn Kaspi says Avraham saw Sarah laughing in his prophecy, but she did not really laugh.

Beliefs about angels – Rambam⁸¹ is consistent with his general approach towards angels that any seeing or talking of a מלאך did not really happen rather was in a prophecy or dream, though he does bring some exceptions where the word is used to refer to a prophet. Radak and Ibn Kaspi say explicitly that Avraham was sleeping when he prophesied all of chapter 18. It is not clear according to Ibn Kaspi if Avraham imagined this or prophesied this.

How many guests – Ibn Kaspi says Lot had a similar prophecy but he only saw two people as opposed to Avraham who saw three.

Crux of the position

¹ Rashbam uses this exegetical principle in other places as well. See, for instance, his comments to Bereshit 1:27 and 26:25.

² R. D"Z Hoffmann is bothered why the story of Lot does not similarly open with "וירא ה' אל לוט" before detailing how the angels visited him.  This leads him to suggest that the phrase marks some internal vision in addition to the physical manifestation of the angels. 

³ In support of this idea is the fact that the text provides the setting for the story, including the location of Avraham and time of day.

⁴ As evidence Rashbam points to Shemot 3:2-4 where one verse speaks of an angel appearing out of the burning bush and the next verse speaks of Hashem calling from it. R. D"Z Hoffmann points to similar examples in Bereshit 31:11-13, Bereshit 48:15-16, and Shofetim 6:11-14.

⁵ They do not explain, though, why some verses refer to them as "people" and some as "Hashem".  They might suggest that this is simply regular Biblical literary variation.  E. Samet suggests that maybe the different titles represent the perspective of Avraham.  They are called people when he viewed them as such, but in verse 13, when Avraham began to realize that they were angels, the text switches to refer to them as "Hashem". [It is possible that in the opening verse they are called Hashem as well, even though Avraham still thought of them as guests, to hint to the reader that they were in fact angels.]

⁶ If, though, the word means "my masters" one would have expected the vocalization under the nun to be a patach (נַ) rather than a kamatz (נָ).  Shadal, thus, explains that in reality Avraham actually spoke to just the lead angel, and said "my master" rather than "our masters".  The Torah, though, changed his language to use the name of Hashem so as to reveal to everyone that the guest was a messenger of Hashem. [See Bavli Shevuot 35b.]
R. Hoffmann explains more simply that the cantillation mark on the nun sometimes takes a pausal from, elongating the patach to a kamatz.

⁷ He would presumably suggest that in the next verse, when Avraham reverts back to the plural, it is because he is offering all of the angels to wash and eat.

⁸ Thus, it is normal usage for Avraham to address the angels in singular in verse 3 and revert to the plural in verse 4.  For an example of Torah switching between plural and singular verbs when speaking of  a group, see Shemot 19:2: "וַיִּסְעוּ מֵרְפִידִים וַיָּבֹאוּ מִדְבַּר סִינַי וַיַּחֲנוּ בַּמִּדְבָּר וַיִּחַן שָׁם יִשְׂרָאֵל נֶגֶד הָהָר".

⁹ One might question this from the fact that the verse says, "וַיֹּאמֶר לוֹט אֲלֵהֶם", which would suggest that Lot is talking to the angels.  R. D"Z Hoffmann brings the opinion of the Ritva who asserts that the word "אֲלֵהֶם" should not be understood as "to them" but rather as "before them."  Lot's words were addressed to Hashem but were said in the presence of the angels.

¹⁰ See also R. D"Z Hoffmann.  Shadal and Hoil Moshe agree in general, but make an exception regarding verses 18:17-19, which they assumes represent the earlier thoughts of Hashem and not a current speech.  They are presumably picking up on the past perfect language of "וַה' אָמָר".  In addition, Shadal claims that though angels can act and speak on Hashem's orders, these verses speak of thoughts and decision making, which is only in the hands of Hashem (הדבור והמעשה נעשים על ידי שליח, אבל המחשבה והרצון אינם על ידי שליח).

¹¹ N. Leibowitz, Iyyunim BeSefer Bereshit, (Jerusalem, 1992):114-115,  sees in these exceptions an inconsistency in Rashbam's approach which leads her to dismiss it. E. Samet, though, points out that this is actually one of the strengths of Rashbam's reading.  Had the speaker of these statements actually been Hashem it would not be clear why Hashem refers to Himself in the third person, using His name and not the word "me".  According to Rashbam, though, the speaker is the angel who logically refers to Hashem using His proper name.

¹² The other commentators agree that the angels were supposed to speak to Avraham about Sedom, but it is unclear if they view the news of Yitzchak's birth as of equal import or if they also think this was just tangential.

¹³ Hashem had just told Avraham that Yitzchak was to be born at the end of Chapter 17.

¹⁴ If so, one would have expected them to be called angels in 18:22 after Avraham realized in verse 17 they are not people according to him.

¹⁵ Since it is so expected that angels know what is going on, Rashbam is bothered by the fact they would need to ask Avraham "where is Sarah" and thus suggests that this was really just a way of opening the conversation.

¹⁶ See also Josephus.

¹⁷ See also R. D"Z Hoffmann who brings the opinion of Seder Eliyahu Rabbah 13 that the angels ate in deference to Avraham.

¹⁸ He notes that Avraham probably did not bow before every passer-by.

¹⁹ Hoil Moshe responds that since they had assumed the form of men, Avraham treated them as such, and they, in turn, ate.

²⁰ See also Philo.

²¹ N. Leibowitz, Iyyunim Besefer Bereshit (Jerusalem, 1992): 116-117, asserts that according to them, 18:1 concludes the story of Chapter 17, rather than introducing the events of Chapter 18. As such, the story of the angels is totally unconnected to the initial revelation of verse 1. 
E. Samet argues that if this is true, the story of the angels would seem to start in the middle.  It opens with a series of pronouns (...וַיִּשָּׂא עֵינָיו), the subject of whom would be unknown if this is the beginning of  a story.  In addition, he suggests that from Ramban's own words, he seems to view the entire two chapters as part of Avraham's reward.  This, too, though is difficult since there is no hint in the text that the vents are connected to the circumcision.  In addition, there would seem to be disproportionate discussion of the reward (2 chapters) compared to the good deed (several verses)..

²² In this he follows  Bavli SotahSotah 14aAbout the Bavli, Bavli Bava Metzia, Tanchuma Vayera 2, and  Tanchuma Ki Tisa 15.  Cf. Bereshit Rabbah47:10About Bereshit Rabbah

²³ This approach anthropomorphizes Hashem, having Him act as humans.  Cf. Bavli SotahSotah 14aAbout Bavli Sotah which asserts that one should learn from these deeds of Hashem and do the same.

²⁴ Ramban points to Bereshit 32:2 and Vayikra 9:23 as parallel cases where Hashem similarly appears to people without speaking, simply as a show of honor, to reward them for keeping a commandment. R. Elhanan Samet, עיונים בפרשת השבוע סדרה שניה, בראשית (ירושלים, תשס"ד): 59-81, questions Ramban's prooftexts, suggesting that cases where there is something tangible to see (such as "מַלְאֲכֵי אֱלֹהִים" and "כְבוֹד ה'") are different than our case in which Hashem appears prophetically.  In the former, there is no need for an accompanying speech since a physical form appears as a sign, yet the language of "וַיֵּרָא ה" is almost always followed by a speech. See, for instance, Bereshit 12:7, 17:1, 26:2,24, and 35:9-10.

²⁵ As evidence that people stand before another when making a covenant he points to Devarim 29:9 and Melakhim II 23:2.  He also points to the phrase "וַיִּפְגְּשֵׁהוּ ה'" in Shemot 4:24 as another example of Hashem "attending" a circumcision, without any accompanying speech.  This example, though, is difficult as the following phrase,"וַיְבַקֵּשׁ הֲמִיתוֹ" suggests a different purpose to the meeting.  Seforno raises the possibility that our story is the reason behind the custom to prepare a chair during circumcisions.

²⁶ In other words, the content of this revelation is first transmitted to Avraham in verse 20 when Hashem says "זַעֲקַת סְדֹם וַעֲמֹרָה כִּי רָבָּה".  Cf. R"Y Bekhor Shor below.

²⁷ According to R. Saadia Hashem generally makes His presence known to prophets through some type of light, so that they recognize that the voice they hear is that of Hashem.

²⁸ See Ramban who makes this point and further asserts that one should not be bothered by the fact that there is a parashah break in the middle since the topic is all one.

²⁹ Rashi attempts to answer that Mamre is specifically mentioned since he is the one who advised Avraham regarding circumcision. The text includes that it was at the heat of the day to show Hashem had purposefully made it hot so as not to bother Avraham with guests.  Ramban and Seforno simply say that the location is included since that is where Avraham was circumcised.

³⁰ See discussion in above note regarding how these commentators apparently view verse 1 as the conclusion to the events of Chapter 17 and E. Samet's questions on such a reading.

³¹ According to a second opinion in Rashi, as well, Hashem stayed, but at the request of Avraham.

³² All of these are difficult for Rashi, Ramban and Seforno.

³³ See also the discussion in Bavli ShevuotShevuot 35bAbout the Bavli.

³⁴ This explains the vocalization of "נָ"rather than "נַ" as would be expected if the word simply meant "my masters".

³⁵ Cf. Ibn EzraBereshit 18:1,13,33About R. Avraham ibn Ezra who similarly suggests that the word might mean "נביא ה'".  This explanation also solves the problem of the problematic vocalization "נָ" rather than "נַ", as it reads the word "אֲדֹנָי" to mean Hashem and not "my masters".
R. Saadia is consistent in reading the term this way throughout the chapters, assuming that in 19:18, too, Lot is addressing the angels as "men of God".

³⁶ He suggests that this occurs often in the Hebrew language.  As support he points to the phrase "לַי"י וּלְגִדְעוֹן" in Shofetim 7:18 which is short for "חֶרֶב לַי"י וּלְגִדְעוֹן" and Shofetim 16:2 which reads לַעַזָּתִים לֵאמֹר rather than "לַעַזָּתִים הוגד לֵאמֹר".

³⁷ See Bereshit Rabbah48:10About Bereshit Rabbah.

³⁸ Abarbanel agrees with his reading.

³⁹ According to him he said, "אַל נָא תַעֲבֹר מֵעַל עַבְדֶּךָ" three times.

⁴⁰ Ramban also suggests that throughout Torah we see similar switches in language.  Often, when Hashem addresses the nation, but means to speak to each individual therein, He begins with plural language and then switches to the singular. For examples, see Vayikra 18:5,7, Vayikra 19:9 and Devarim 4:29.

⁴¹ On 19:18, as well, Rashi brings the opinion of Bavli ShevuotShevuot 35bAbout the Bavli that Lot's speech "אַל נָא אֲדֹנָי" is directed at Hashem, not the angels.  To explain, if so, why the verse states that "וַיֹּאמֶר לוֹט אֲלֵהֶם", as if Lot were speaking to the angels, Rashi suggests that the first two words of Lot "אַל נָא" were n fact addressed to them.  The word "אֲדֹנָי", though, is attached to the following verse and begins the prayer there.

⁴² The Karaite, Yaakov Kirkisani questions this reading, pointing out that one would have expected Avraham to speak these words to Hashem before he ran to greet the guests in verse 2.

⁴³ Ramban suggests that although Avraham was already aware of this, he had not yet told Sarah.

⁴⁴ Cf. TryphoJustin Martyr, Dialogue with Trypho 56-57 who asserts that two angels came to destroy Sedom and one to announce the birth.  The one who had finished his task did not continue to Sedom.  R. Saadia and Abarbanel do not elaborate on the specific mission of each angel but explain the missing third in the same way.

⁴⁵ He points to Chagai who is called both prophet and "מלאך ה'" (Chagai 1:3,13). See also Bereshit 32:25, Yechezkel 9:2 and Daniel 12:7 which all mention a man (or men) who appear to be angels.  In none of these cases, though, are they referred to as such and one could argue that in fact the verses all speak of human agents and not heavenly ones.

⁴⁶ Abarbanel points out that this logic does not account for all the cases where they are also called "men" by Lot.

⁴⁷ He suggests that they traveled from Avraham to Sedom at supernatural speed (or they would not have been able to arrive by evening after eating and spending the day with Avraham) and are thus called "angels" upon arrival.
According to this reading though, it is not clear why the angels are not so called when they blind the poeple of Sedom, nor why in one verse that describes their saving of Lot they are called angels while in the next they are called people again.

⁴⁸ Rasag explains "וַיֹּאכֵלוּ" from the language of כילוי, and brings a parallel to Shoftim 6:20 even though he says he was a person there.

⁴⁹ For such usages see Bemidbar 13:32, Devarim 7:16 and Yeshayahu 1:20.

⁵⁰ He claims that Hashem did not correct him so that he continue his hosting and hear the news when at peace, seated at a feast.

⁵¹ Abarbanel explains the same.

⁵² According to Ramban, it is Avraham (rather  than Hashem) who responds, "no, you laughed."

⁵³ See the opinion brought by Ibn EzraBereshit 18:1,13,33About R. Avraham ibn Ezra who also posits achronology: וי"א שהוא מוקדם ומאוחר, וכן הוא וישא – וכבר נשא עיניו ועשה כך וכך, ואח"כ נראה אליו השם.

⁵⁴ Though this accounts for the juxtaposition, it does not adequately explain why verse 1 could not have been written in its proper place, after the angels left in 18:16.

⁵⁵ This would explain why the two angels who were heading to destroy Sedom and had no news to share with Avraham nonetheless stopped by.

⁵⁶ Often the Torah uses the term "מַּלְאָכִים" to describe people who are sent by others on some mission. As an example, R"Y Bekhor Shor points to Bereshit 32:4, where Yaakov sends human messengers to his brother and the text calls them "מַּלְאָכִים".

⁵⁷ Since Avraham received more prophecies than the guests, they are referred to as people when speaking to him. Since Lot was not a prophet, they can be called either "מַּלְאָכִים" or "men' when interacting with him.
Ralbag points to Bereshit 16 (the story of Hagar and the "מלאך") as another example where a prophet is called a "מלאך" because he is talking to someone on a lesser level.

⁵⁸ According to him, the word "תַעֲבֹר" is not second person masculine but rather third person, feminine and refers to the "חבורה" of prophets.  In this he differs from R. Elazar in Bavli ShabbatShabbat 127aAbout Bavli Shabbat who claims that Avraham requested that Hashem stay while he dealt with the guests.  R"Y Bekhor Shor rejects that possibility because according to him, Hashem had not yet revealed Himself to Avraham and was not in the midst of conversing with him.  In fact, he posits that it is specifically because he was not busy with Hashem that Avraham had no problem inviting the guests to stay and eat etc.

⁵⁹ He does not address the problematic vocalization of "אֲדֹנָי" with a kamatz, but interestingly, Ibn Ezra writes that in some manuscripts the word appears with a patach.

⁶⁰ R"Y Bekhor Shor, though, assumes that the next verse is a prayer aimed at Hashem. Presumably he is motivated by the fact that Lot is speaking of killing and saving lives, something which is only in the hands of Hashem. Cf. Rashi above.

⁶¹ Ralbag might be hesitant to read this as Hashen Himself because that would require one to assert that Avraham received prophecy while awake, in the midst of dealing with the guests. He suggests that it is possible that due to Avraham's great prophetic status, he was able to do so, but seems to prefer the other reading.

⁶² He points to Bereshit 25:23 as another example where a prophet is called "Hashem". 

⁶³ For proof that angels do not eat, he points to Shofetim 13:16.

⁶⁴ See Melakhim II 6:18 where Elisha the prophet also blinds his enemies. Abarbanel questions this parallel, arguing that there it is explicit that Elisha prayed to Hashem and that it was Hashem who blinded the enemies.  One might answer that here too the prophets prayed but the fact is simply not mentioned in the text.

⁶⁵ He further asserts that if they were prophets of Hashem, they would have also needed to be circumcised, a fact that would have been shared by the Torah.

⁶⁶ Ibn Ezra asks this question as well and responds that the prophets were coming to announce the birth to Sarah, not to Avraham.

⁶⁷ See Ibn Ezra who dismisses the question by pointing to Shemot 11:10, which attributes all the wonders in Egypt to Moshe and Aharon, despite the fact that they were Hashem's doing.

⁶⁸ Abarbanel proves that the vision in 18:1 does not stand alone since later verses (such as 18:20 and 22) mention Hashem speaking. See, though, Rashbam above who explains these verses to refer to the angel.

⁶⁹ Cf. Bavli Sotah above. This approach, thus, needs to explain why Avraham is referred to without a name in 18:1 (which works better if the verse is a continuation).

⁷⁰ He follows Bereshit Rabbah 50:2 that one of the guests came to share the news about the child, the second to destroy Sedom, and the third to save Lot.

⁷¹ In 19:15 they save Lot like angels, and in 19:16 the guests held on to Lot like humans, but it is unclear what is angelic about them coming to Sedom.

⁷² Rambam and Ibn Kaspi only say explicitly about 18:3.

⁷³ Radak proves 19:18 is the angels since Lot said to them in plural, and Eliyahu and Elisha brought people back to life so too angels can.

⁷⁴ Radak and Ibn Kaspi seem to say they did blind Sedom.

⁷⁵ Bereshit Rabbah 51:9 moves over the question to the wife of Lot saying she went to all her neighbors asking for salt for the guests and that is how they knew.

⁷⁶ One can similarly posit that the vision ends after the guests leave in chapter 18.

⁷⁷ He does bring an option the prophecy continued to chapter 19.

⁷⁸ See Devarim 29:22, Yeshayahu 1:9, 13:19, and more.

⁷⁹ Abarbanel himself is not convinced and for this reason he says the angels appeared to Avraham in reality.

⁸⁰ But it is not clear if Lot just imagined or prophesied this.

⁸¹ Rambam does not say like R. Yosef Bekhor Shor and Ralbag either that the guests were people, because he thinks there are different levels of prophecy, the highest one being appearance of Hashem in the day which only Moshe reached, therefore he can not say Hashem appeared to Avraham separately in 18:1 in the middle of the day.