Endangering Sarai in Egypt/2

Endangering Sarai in Egypt

Exegetical Approaches

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Overview

The commentators' evaluations of Avram's actions in Egypt vary widely.   The vast majority, no doubt hesitant to view Avram's earliest recorded actions negatively, attempt to justify his behavior. Most of these assume that Avram had not meant to endanger Sarai at all. Radak, thus, asserts that Avram acted unintentionally; he was simply unaware of the danger that his wife's beauty would bring to them in Egypt.  R. Nissim, in contrast, portrays a very aware and calculating Avram, who had devised a ruse to avoid the potential danger, though it proved to be unsuccessful.

A third group of commentators maintain that Avram knowingly endangered Sarai's honor, but this was justified due to his desire to save his own life.  According to this position, preservation of human life trumps all other considerations.  Finally, Ramban and Cassuto each fault Avram for his actions in this story, criticizing his lack of faith in Hashem.  Ramban deplores both Avram's decision to leave Israel and the endangering of Sarai, while Cassuto criticizes his deceiving of Paroh and the Egyptians.

Endangered Unwittingly

Avram never intended to place his wife in danger and had not thought that she would be taken to Paroh's palace.  This position subdivides regarding what Avram was thinking in acting as he did:

Unaware of Danger

Avram simply did not recognize that going down to Egypt would endanger Sarai until it was too late.

Sources:Bavli Bava Batra16aAbout the Bavli, Bereshit Rabbah40:4About Bereshit Rabbah, TanchumaLekh Lekha 5About the Tanchuma,¹ RambamCommentary on the Mishnah Avot 5:17About R. Moshe Maimonides, RadakBereshit 12:11-17About R. David Kimchi, Akeidat YitzchakBereshit #16About R. Yitzchak Arama, AbarbanelBereshit 12:10Bereshit 12:16About R. Yitzchak Abarbanel²

Descent to Egypt – Most of these commentators assert that Avram only left the land promised to him by Hashem because the severe conditions brought about by the famine left him no choice.³  As such, his actions are not problematic. Both Radak and Abarbanel further stress that Avram only planned to leave temporarily and was thus not rejecting Hashem's chosen land.

"הִנֵּה נָא יָדַעְתִּי...‏" – Most of these commentators define the word "נָא" in this verse as  "now".⁴ Avram had either truly never noticed Sarai's beauty beforehand,⁵ or only first appreciated its ramifications now, when contrasting Sarai with the Egyptians.⁶ It was thus, only upon entry into Egypt, that Avram recognized that there was potential danger.⁷  Radak and Abarbanel maintain that had he known sooner, Avram would never have gone down.

"וְהָרְגוּ אֹתִי וְאֹתָךְ יְחַיּוּ" – According to Radak, Akeidat Yitzchak, and Abarbanel, in these words, Avram is pointing to the dangers that faced both him and Sarai – for him, death, and for her, an equally terrible fate, to be left alive so as to be raped.

"וְחָיְתָה נַפְשִׁי" – Is his life more important? Radak explains that Avram thought that Sarai would be in worse danger if he were dead rather than alive.  Although the Egyptians might take her either way, Avram's presence would shame them into minimizing their base actions, whereas his death would leave Sarai at the mercy of their whims.⁸

Why a sister specifically? Radak might maintain that Avram thought he could best watch over Sarai if others believed that they were related (but not married).  This way they could live together, and their kinship would help ensure that the Egyptians acted with at least a modicum of conscience.⁹

Lying and leading Egypt to sin – Most of these commentators would likely maintain that lying is not problematic if it will help save a life, and that telling the truth would not have stopped the Egyptians from sinning anyway.¹⁰ Akeidat Yitzchak suggests that even Paroh agreed that the ruse was valid in light of the Egyptians' reputation, and that he complained only that Avram had not disclosed the truth to him on an individual level.

"לְמַעַן יִיטַב לִי בַעֲבוּרֵךְ" – Asking for riches? Radak, Akeidat Yitzchak, and Abarbanel explain that this clause is parallel to and defined by the immediately following one, "וְחָיְתָה נַפְשִׁי בִּגְלָלֵךְ".‎¹¹  It is inconceivable that Avram would desire to get rich off the shame of his wife.¹²  Moreover, he had no need of riches, being independently wealthy.  The only reason he even accepted Paroh's gifts was his fear of displeasing him.¹³

Why punish Paroh? Radak and Akeidat Yitzchak suggest that the plague should be viewed as a deterrent that prevented Paroh from touching Sarai, rather than a punishment for doing wrong.¹⁴

Why does Avram repeat his actions in Gerar? The repeated actions in Gerar are difficult for this position as it would be hard to say that there too Avram was taken by surprise.¹⁵

Hoped to Avert Danger

Avram's actions were part of a calculated plan which was meant to protect Sarai and prevent her from being forcibly taken by the Egyptians.

Sources:Bereshit Rabbah40:5About Bereshit Rabbah, TanchumaAbout the Tanchuma, RashiAbout R. Shelomo Yitzchaki, Ba'alei HaTosafot, RanBereshit 12:11About R. Nissim Gerondi, AbarbanelBereshit 12:10About R. Yitzchak Abarbanel, SefornoAbout R. Ovadyah Seforno, Ma'asei Hashem, ShadalBereshit 12:11-13About R. Shemuel David Luzzatto, R. S"R HirschAbout R. Samson Raphael Hirsch, MalbimAbout R. Meir Leibush Weiser, Hoil Moshe

The Plan

• Prolong marital negotiations ­­– Most of these commentators assert that Avram meant to act as Sarai's guardian who could negotiate her nuptials,¹⁶ and planned to ask for such a high dowry that no one would be able to meet it.  During the prolonged discussions, Avram would be able to get provisions enabling him to return to Israel before any harm was brought to Sarai.¹⁷
• Pass Sarai off as married ­­– Chizkuni, instead, suggests that Avram told the Egyptians that Sarai was indeed married but that her husband was overseas. Unable to kill her spouse, and fearful of committing adultery, they would thus leave Sarai alone.¹⁸
• Hide Sarai ­­– According to Bereshit Rabbah, Tanchuma, and Rashi, Avram was hoping to hide Sarai during their stay.¹⁹

Descent to Egypt –

 All of these sources justify Avram's decision, but for different reasons:

• Test from Hashem ­­–  Rashi, Ran, and Malbim count the famine as one of Avram's ten trials,²⁰ asserting that Hashem was testing whether Avram would complain when forced out of the land.  As such, they assume that Hashem intended Avram to leave and viewed his acceptance of the situation as a show of faith, rather than a lack thereof.²¹
• No reliance on miracles ­­– R. Hirsch and Malbim maintain that one is not supposed to rely on miracles,²² but must make whatever efforts one can to deal with a problematic situation.²³
• Caring for others ­­– The Ran suggests that had Avram only needed to care for himself and Sarai, he would likely not have descended to Egypt, but since he felt responsible for many others and desired to continue his hospitable ways, he chose to go down.
• Plan to save Sarai ­­– Ran points out, though, that even the necessity to escape death from famine can neither explain nor justify a decision to endanger Sarai's honor, leading him to conclude that Avram descended with a ruse which he thought would prevent any problems.²⁴

"הִנֵּה נָא יָדַעְתִּי...‏" – These commentators split, with some²⁵ suggesting that "נָא" means "now",²⁶ and others viewing the term as a figure of speech or a sign of emphasis.²⁷  If the latter, Avram is simply saying, "behold, I know you are beautiful..." as a preface to the discussion of this fact's ramifications.

"וְהָרְגוּ אֹתִי וְאֹתָךְ יְחַיּוּ" – Ran, Ma'asei Hashem, and R. Hirsch assert that Avram is equating the potential fates of both himself and his wife; Avram will die, and Sarai be left alive to have her honor harmed. When he requests that Sarai pose as his sister, his purpose is to save them both.

"לְמַעַן יִיטַב לִי בַעֲבוּרֵךְ" – Asking for riches? Most of these commentators could say, like Seforno, that Avram is referring to the dowry that he plans to ask of the Egyptians who seek to marry Sarai.²⁸ Malbim defends this reading by pointing out that the word "בַעֲבוּרֵךְ" means "on your behalf", rather than "because of you" ("בִּגְלָלֵךְ‎").²⁹

"וְחָיְתָה נַפְשִׁי" – Is his life more important? Avram was not planning on saving himself at Sarai's expense, but rather trying to save both.

Why a sister specifically? For most of these commentators, Avram chose to pass himself off as Sarai's brother since only such a relative could negotiate her dowry and push off potential suitors.

Lying and leading Egypt to sin – This position would likely suggest that in cases of potential loss of life, lying is permissible.  In addition, according to most of these commentators, since Avram's goal was to deflect potential suitors, there is no issue of leading others into sin.

Why punish Paroh? According to Chizkuni, Paroh believed that Sarai was married and nonetheless took her. The fact that he did not know that Avram specifically was her spouse is irrelevant.

Why does Avram repeat the actions in Gerar? Since Avram's plan was actually a logical one which could have worked in most situations, it made sense to try again.³⁰

Self-preservation

Avram's conduct was motivated by a desire to save himself. Placing Sarai in potential danger was justified in face of the supreme value assigned to preservation of life.

Sources:Pirkoi b. Bavoi(Ginzei Shechter I, pp. 19-20)About Pirkoi b. Bavoi, RalbagBereshit 12 Toelet 3About R. Levi b. Gershon, AbarbanelBereshit 12:10About R. Yitzchak Abarbanel³¹

Descent to Egypt – This approach lauds Avram's decision to escape the almost certain death due to famine, rather than stay in Israel and trust that Hashem would save him.³²  Since commandments were given to live by, temporarily leaving the land to save one's self is seen, not as a transgression, but rather as an act to be emulated.

"הִנֵּה נָא יָדַעְתִּי...‏" – Ralbag does not read any significance into the word "נָא", and he assumes that Avram had always recognized Sarai's beauty.  Avram is simply remarking upon it now in the context of the danger that this fact brings to his life.³³

"וְהָרְגוּ אֹתִי וְאֹתָךְ יְחַיּוּ" – According to Ralbag, the two parts of the phrase are a contrast to each other.  Avram is telling his Sarai that the Egyptians will kill him,  leaving only her alive, and thus emphasizing that the danger is only to him rather than to Sarai.

"וְחָיְתָה נַפְשִׁי" – Is Avram's life more important? Although these commentators agree that Avram was placing his life before the honor of his wife, they differ in the justifications they offer for this:

• Pirkoi b. Baboi asserts that all other transgressions can be violated in order to save a life.³⁴  Even potential danger to life overrides a potential prohibition of relations, in a case where the prohibited act is being coerced.³⁵ 
• Abarbanel instead suggests that Avram was convinced that Sarai's being taken was inevitable.  If so, nothing was to be gained by Avram martyring himself, and it is logical that he should try to at least save himself.

Why a sister specifically? According to this approach, there was no special need for Avram and Sarai to claim a sibling relationship, but the ruse would easily enable them to continue living together.

Lying and leading Egypt to sin – Though the commentators do not address the issue explicitly, they would likely say that lying is permissible in face of danger to one's life, even if it causes a stumbling block for another.

"לְמַעַן יִיטַב לִי בַעֲבוּרֵךְ" – Asking for riches? While Abarbanel assumes that the good to which Avram is referring is that his life be saved, Ralbag seems to suggest that he is alluding to presents or honor that would be given to him by the Egyptians who desired Sarai.  He does not address the issue of the insensitivity of such an action.

Why punish Paroh?

Why does Avram repeat the actions in Gerar? Since preservation of life trumps all, it is not surprising that Avram acted similarly any time he found himself in a life-threatening situation.

Avram Sinned

Avram's actions in descending to Egypt and endangering Sarai were problematic, and Avram was punished for them.

Sources:RambanBereshit 12:10-13Bereshit 20:12About R. Moshe Nachmanides, ZoharPart 1, p. 81bAbout the Zohar, U. Cassuto³⁶

Descent to Egypt – Ramban views Avram's decision to leave Israel as an expression of lack of faith in Hashem.³⁷  He claims that Avram was, in fact, punished severely for his actions, and the decree of slavery in Egypt was a direct outcome of this story.³⁸  As evidence, he points to the many parallels³⁹ between the two episodes,⁴⁰ suggesting that the enslavement was a measure for measure punishment for Avram's deeds.

"וְחָיְתָה נַפְשִׁי" – Is Avram's life more important? Ramban and Cassuto fault Avram for trying to save himself at the expense of endangering Sarai, claiming that Avram should instead have trusted in Hashem to save them both.⁴¹

"הִנֵּה נָא יָדַעְתִּי...‏" – Ramban  maintains that the word "נָא" describes any fact which is a continuous truth,⁴² pointing to its usage in Bereshit 16:2 and 19:8.  The phrase does not connote that Avram first came to recognize Sarai's beauty upon entry into Egypt, but rather that he had known it all along.

"וְהָרְגוּ אֹתִי וְאֹתָךְ יְחַיּוּ" – Cassuto suggests that, in these words, Avram is alluding to two evils, that he will be killed, and worse, that Sarai will be left alive, without his protection, to be raped.

Why a sister specifically? Cassuto maintains, like the Ran above, that Avram was hoping to pass as Sarai's guardian so as to negotiate her nuptials and thus deflect potential suitors.  In contrast to the Ran, though, he views this ruse as problematic, asserting that Avram should not have trusted in his own cleverness (which in the end failed him), but in Hashem.

Lying and leading Egypt to sin – Cassuto views this as Avram's main sin. He should have had faith in Hashem's salvation rather than resort to trickery and his own ability to outwit the Egyptians.  Cassuto asserts that, in the end, Avram's plan totally backfired. His fear that the Egyptians might take Sarai never materialized, and what he had not planned for, that Paroh might be interested in his wife, did occur.  In the end, it was Avram's lie itself that endangered Sarai.  Passing himself off as Sarai's brother is what enabled Paroh to take his wife.⁴³

"לְמַעַן יִיטַב לִי בַעֲבוּרֵךְ" – Asking for riches? Ramban minimizes the possible negative connotations of Avram's words by explaining that the good refers to  the provision of sustenance during the famine, not riches. In addition, in paraphrasing Avram's thoughts, Ramban puts them into plural language, thereby having Avram include Sarai as a beneficiary of this "good".⁴⁴ Cassuto alternatively suggests that the good that Avram speaks of refers to the saving of his life.⁴⁵

Why punish Paroh? According to both Ramban and Cassuto, Paroh took Sarai without first asking about her marital status, and as such was responsible for his actions.⁴⁶

Why does Avram repeat the actions in Gerar? Due to this point, Ran rejects Ramban's criticism of Avram, asking how is it possible that Avram, after being punished, would have repeated his sin only a few chapters later. Ramban, in his Derashat Torat Hashem Temimah,⁴⁷ anticipates this objection and suggests that Avram never knew for what he was being punished in the Covenant of the Pieces, and as a result he repeated his error.

¹ The Midrash also mentions Avram's attempts to protect Sarai by hiding her in a box, combining this approach with the one below.

² Abarbanel combines this approach with the others below.

³ In explaining the necessity, Tanchuma and Abarbanel point to the harshness of the famine, while Radak and R. Yitzchak Arama note the many members of his household and the numerous cattle for which Avram needed to provide.  Abarbanel brings evidence for this assertion from the opening verse of the story which emphasizes that Avram left only "כִּי כָבֵד הָרָעָב בָּאָרֶץ". Had the situation been less severe, Avram would not have gone down.  To further support this positive evaluation of Avram's decision to leave the land, both Akeidat Yitzchak and Abarbanel points to the discussion in Bavli Bava Kamma60bAbout the Bavli which sees Avram's actions as worthy of emulation.

⁴ Radak is somewhat of an exception.  Though he agrees that the word means "now", he suggests that in this case it is simply being used as a figure of speech (similar to its usage in Bereshit 19:2 and 18).  Thus, according to him, one should not conclude from this statement that Avram had never before recognized that his wife was beautiful.  See נָא for more about the usage of the word in Tanakh.

⁵ Bavli Bava Batra, Tanchuma, and Rambam understand the verse in this way, suggesting that due to Avram's great modesty he had never looked carefully at his wife.  Tanchuma maintains that he only did so now because he happened to see her reflection in a river, "shining like the sun".

⁶ See R. Zeira in Bereshit Rabbah, Radak, Akeidat Yitzchak, and Abarbanel. Abarbanel asserts that until now Avram had not thought that there was anything extraordinary about Sarai's beauty, since there were other women who were comparable to her in Canaan.  Only upon arrival in Egypt, when he found himself surrounded by "dark-skinned and ugly" people, did he realize that she might be deemed beautiful by the locals.  Akeidat Yitzchak instead posits that Avram only realized the full extent of the moral depravity in Egypt when he was about to enter the country.

⁷ Akeidat Yitzchak asserts that Avram had weighed the relative dangers of staying in Canaan (almost definite death due to famine) and what he deemed as only an unlikely possibility that there would be danger in Egypt, and that he had unfortunately underestimated the latter.  He points to the four lepers of Melakhim II 7 for another case where people weighed the likely death resulting from hunger against the potential hazards of entering enemy territory and similarly opted for the latter.

⁸ In this, Radak is similar to the approach below that suggests that Avram's actions were aimed at protecting Sarai.

⁹ See above that Radak assumes that the Egyptians' embarrassment in front of others might not prevent their licentious actions entirely, but would at least put them in check.  Abarbanel, instead, follows in the path of the Ran, asserting that Avram planned to portray himself as Sarai's guardian, in charge of her nuptials, enabling him to prevent her from being taken by potential suitors.  For elaboration, see below.

¹⁰ It would have led instead to the murder of Avram and the subsequent seizing of Sarai.  Though the specific sin of adultery might be eliminated, the alternatives are not better.

¹¹ Compare Devarim 5:30, Devarim 6:24 and Yirmiyahu 38:20 where the two phrases are similarly paired and seem to be equivalent in meaning.  The difficulty for this position is the fact that the very same words, "וּלְאַבְרָם הֵיטִיב בַּעֲבוּרָהּ", appear several verses later where they refer to the giving of riches to Avram.

¹² As proof of the absurdity of the possibility, Radak points to the story of Sedom where Avram had a legitimate conqueror's rights to all of their possessions but nonetheless refused to take them.

¹³ According to Abarbanel, even in the end, Avram does not accept gifts from Paroh.  He asserts that the referent of the words, "וּלְאַבְרָם הֵיטִיב בַּעֲבוּרָהּ" is actually Hashem (mentioned in the next verse) and that the verb in the clause is in the past perfect tense. As one might question why the text would be sharing this information now, Abarbanel answers that the verses are simply saying that Hashem had previously given Avram wealth due to Sarai's righteousness, and here too, He is plaguing Paroh on her behalf.

¹⁴ Akeidat Yitzchak adds that although Paroh would not have touched Sarai had he known that she was married, Hashem did not prevent him from taking her  "כדי לפרסם שם גדולתו".  Hashem preferred to teach all how he protects his loyal followers.

¹⁵ Radak and Abarbanel, who maintain that Sarai's beauty was only in contrast to the Egyptians, could suggest that Avram did not think it would be a problem elsewhere.  Nonetheless, one might imagine that after the near disaster in Egypt, Avram would have been wary of a repeat scenario.

¹⁶ See B. Eichler, "On Reading Genesis 12:10-20" in Tehillah le-Moshe: Biblical and Judaic Studies in Honor of Moshe Greenberg, ed. M. Cogan et al. (Winona Lake, 1997): 32-38, who brings much evidence from the Ancient Near East for such guardian roles of brothers.

¹⁷ If some potential suitor became problematic, Avram figured he would simply return to Israel.  He had never thought of the possibility that it would be Paroh himself who would desire Sarai and simply take her without any discussion.

¹⁸ The working assumption of this theory is that the Egyptians had no qualms in committing murder but were very hesitant to touch a married woman.

¹⁹ See Jubilees 13:10-16About Jubilees 13:10-16 and the Genesis Apocryphon, which have Avram in Egypt for a full five years before Sarai was taken, suggesting that he was actually successful in protecting his wife for that long. The Torah does not mention the duration of Avram's stay, but it also does not contradict this possibility.

²⁰ See also R. Pinchas and R. Yehoshua b. Levi in Bereshit Rabbah.

²¹ Ran further argues that since Hashem would not have tested Avram if he were to fail, one must conclude that Avram's actions were not sinful.

²² Malbim also points out that Avram was humble enough not to expect that Hashem would bring a miracle on his behalf.  To further defend Avram, he adds that Avram was planning on moving to Egypt only temporarily, so it is not as if he was uprooting himself totally from Hashem's Promised Land.

²³ R. Hirsch adds that it is easy for a modern person to argue that Avram should have trusted in Hashem, since, from history, one knows that He always cares for the righteous and would never forsake them.  Avram, though, did not yet have that experience, as there had been no "Avrahams" before him.  It was only through trials like this one that we were all able to learn this lesson.

²⁴ See point above for elaboration.

²⁵ See Tanchuma, Rashi and others that the word "נָא" means "now.

²⁶ Thus, Avram's words reveal that he first appreciated Sarai's beauty, or the danger it brought, upon entry into Egypt.

²⁷ See Ran, Shadal, R. Hirsch, and Malbim.

²⁸ See Ma'asei Hashem, Malbim and R. Hirsch similarly. Abarbanel and Shadal, like Radak above, instead equate the term with the immediately following phrase "וְחָיְתָה נַפְשִׁי בִּגְלָלֵךְ" while Ran asserts that the good refers to the fact that the plan will ensure that the Egyptians allow him to stay in the land and do not chase him away. Rashi, in contrast, says that the phrases refers to getting gifts. He is likely motivated by the parallel words in verse 16 which are explicitly followed by a list of gifts, but does not explain how Avram could really say to his wife that he will be enriched via her loss of honor.

²⁹ Avram will remain alive because of Sarai's deeds, but he will accept gifts only on her behalf, as part of the nuptial negotiations.

³⁰ One might suggest that, regardless,  Avram should have learned to be wary of the possibility that the king would take her and plan accordingly.

³¹ He combines this approach with the two above.

³² Abarbanel explicitly combats the position of Ramban below that views Avram's actions as problematic.

³³ See above that Abarbanel combines the above approach, that Avram was unaware of the danger to Sarai with this one.  He thus understands the word "נא" to mean "now" and suggests that only upon arrival in Egypt did Avram recognize his wife's beauty, as contrasted with the local women.

³⁴ Pirkoi b. Baboi is partially motivated by a polemic with the Karaites who denied the principle that salvation of life allows one to disregard certain commandments.

³⁵ One might question this assumption from Bavli Sanhedrin 74a which asserts that preservation of life overrides all commandments except the cardinal sins of murder, idolatry, and illicit relations.  Pirkoi b.Baboi would apparently respond that this does not apply to a case where it is uncertain that the prohibitions will be violated.

³⁶ While the Ramban focuses on the problematic decision to go down to Egypt and endanger Sarai, Cassuto emphasizes Avram's lack of faith once in Egypt that led him to lie in order to save his wife.

³⁷ Cassuto does not fault Avram on this point, asserting that he did so against his will, only due to the severity of the famine.  His intentions were only to stay there temporarily ("לָגוּר") and as soon as the danger passed to return to the land promised him by Hashem.

³⁸ For elaboration, see Ramban's position in  Purposes of the Egyptian Bondage.

³⁹ Both stories open with a famine causing those affected to descend to Egypt.  Once there, the Egyptians oppress them leading Hashem to punish the oppressors via plague.  In the end both Avram and the nation leave with great wealth.
The Genesis Apocryphon and Jubilees, interestingly, add another potential parallel between the two stories. They both suggest that Avram stayed in Chevron for two years and then in Egypt for five years before Sarai is taken. Michael Segal, in his article, "The Literary Relationship Between the Genesis Apocryphon and Jubilees: The Chronology of Abram and Sarai's Descent to Egypt", Aramaic Studies 8 (2010): 71-88, suggests that the works are alluding to the similar chronology in the Yosef story. The brothers first go to Egypt after two years of famine and stay there, unharmed, for the remaining five years. Only afterwards do troubles start.

⁴⁰ Ramban points to R. Pinchas in Bereshit Rabbah who also enumerates the many similarities between the stories, asserting that Hashem told Avram, "צא וכבוש את הדרך לפני בניך". R. Pinchas, however, does not view Avram's actions as a sin.  In fact, Abarbanel points to his words in order to justify Avram's descent, asserting that Hashem planted the idea in his head so that he could pave the way before his children.
See, though, A. Shammah,"תהליכי גיבוש ותמורות בעמדתו הביקורתית של רמב"ן על אברם בירידתו מצרימה", Megadim 50 (2009):199-220, who suggests that Ramban might have originally agreed with the Midrashic take and only later changed his stance to view Avram more critically.  Thus, when he wrote the first part of his comments on verse 10, he might have simply been showing how Avram set in motion, on God's bidding, what was to come. Similarly, in his Derashat Torat Hashem Temima, Ramban only mentions the sin of endangering Sarah, and not the descent to Egypt. Thus, Shammah posits that perhaps it was only later that Ramban added the last few lines ("דע כי אברהם אבינו חטא").    It should be noted, though, that this section is found in all the manuscripts of Ramban and does not seem to be  a later edition, so if Ramban's view changed over the years, the change was early enough that it found its way to the earliest versions of the commentary.

⁴¹ In his commentary on the Torah, Ramban suggests that Avram asked Sarai to do this during many of their travels, suggesting that the ruse in and of itself might not have been such a bad idea. Perhaps what troubled Ramban was the decision to go to Egypt specifically, since its inhabitants were likely to harm Sarai's honor.   If so, this would explain why Ramban does not criticize Avram in the parallel story in the land of the Philistines. 
In his דרשת תורת ה' תמימה, in contrast, Ramban does not mention the repeated usage of the plan and does assume that Avram sinned in Gerar as well. See Shammah, as per the above note, who suggests that the different works might reflect different stages in Ramban's read of the story.

⁴² In Ramban's words: על כל דבר הווה ועומד יאמרו כן, כי הוא רומז על הענין לומר שהוא עתה ככה. הנה נא ידעתי כי אשה יפת מראה את, מאז ועד עתה.

⁴³ Ramban, in contrast, does not fault Avram for this action.  He asserts that the Egyptians took Sarai without asking about her marital status at all and only afterwards did Avram say that he was Sarai's brother to save himself from potential death. [He further maintains that Sarai herself did not say anything one way or the other and simply kept silent on the matter.] Thus, Avram's words in no way caused the near catastrophe and Avram did not lead anyone into sin.

⁴⁴ See Shammah (ibid) who makes this point. He asserts that this more positive reading of Avram's words reflects Ramban's wavering in his criticism of Avram's actions.

⁴⁵ These words are parallel to those at the end of the verse, "וְחָיְתָה נַפְשִׁי בִּגְלָלֵךְ".

⁴⁶ Cassuto adds that the plagues were more of a warning to keep Paroh from adultery than a punishment.

⁴⁷ He does not address the issue in his Torah commentary, and does not even criticize Avram in the second story.