Chronology – Shemot 18/2

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Chronology – Shemot 18

Exegetical Approaches

Overview

When did the various events of Chapter 18 occur? Did they take place before the events of the chapters which follow? Or did they happen only after the Decalogue or the building of the Tabernacle? There are three basic categories of possibilities which subdivide further.  Many Midrashim assume that the entire chapter is in chronological order and that Yitro both arrived and left before the revelation at Sinai.  In contrast, R. Saadia and Ibn Ezra argue that the whole story is out of order.  Finally a whole host of other exegetes split the chapter and suggest various permutations for which parts of the story happened before the Decalogue and which occurred only later.

Completely Chronological

All of Chapter 18 occurred before the Decalogue, and the entire chapter is in its chronological place. There are two variations of this position:

In the 2nd Month

Yitro visited at the end of the second month (of the first year) while the nation was still camped at Rephidim, and all of the events recorded in Chapter 18 occurred before the nation arrived at Mount Sinai in Chapter 19.

Chronology – This opinion is consistent with the view adopted by many exegetes that the Torah is in chronological order. According to this position, one can also readily explain why Chapter 18 appears here despite the fact that it interrupts a unit detailing the nation's sojourns from Yam Suf to Sinai (see Context).
Yitro at Sinai – However, Pesikta DeRav Kahana and Tanchuma (and perhaps the Midrash Aggadah – Buber), appear to be motivated, not by the chronology factor, but rather by a desire to limit the revelation at Sinai to the Children of Israel.2 They explain that only those who were enslaved in Egypt had earned the right to participate in the celebration of the giving of the Torah, and thus Yitro could not attend. Therefore, the Pesikta and Tanchuma claim that all of Chapter 18, including Yitro's departure, must have taken place before the giving of the Decalogue.3
Moshe's family at Sinai – The chronology of Chapter 18 has dual implications for who was present for the revelation at Sinai. On one hand, if the entire chapter occurred before the Decalogue, then Yitro was not present. On the other hand, as long as Yitro arrived before the Decalogue, Moshe's children were present. This is made explicit by the Tosafists brought in Tosafot HaShalem 18:13:1,6 and the Long Commentary of the Tur (18:13) who argue that it is inconceivable that Moshe's sons did not experience the revelation at Mount Sinai.4
"At God's mountain"(18:5) – It is not clear how these sources would explain this verse. It is possible that they might explain like Targum Yerushalmi (Yonatan)Shemot 18:5About Targum Yerushalmi (Yonatan) that the Israelites were encamped only near Mt. Sinai. They might also maintain like Ramban below that this phrase does not describe where the nation was camped, but rather where Yitro initially stopped on his way to visit Moshe – see discussion below.
Shemot 18 and Devarim 1 – Ibn Kaspi Shemot 18:1 in his first option maintains that both stories describe the same appointment of judges – see here, and thus the account in Devarim must also be speaking about the first year. As the context in Devarim 1 is the events of the second year, Ibn Kaspi needs to explain that the phrase "at that time" in Devarim 1:9 does not imply that the judicial appointments occurred at the same time as the rest of the events of that chapter, but rather a year prior to them (see here for an analysis of the phrase "at that time" in Tanakh). Alternatively, one could suggest that Devarim 1 is a retelling, not of the story of Shemot 18, but rather of the story in Bemidbar 11. This appears to be the second option of Ibn Kaspi.5
Chovav in Bemidbar 10 – Mendelssohn posits that Yitro and Chovav were not the same person, but rather brothers (see Yitro's Names), and thus there is no contradiction between Yitro's departure in Shemot 18 and Chovav's presence in Bemidbar 10. However, Ibn Kaspi6 assumes that Yitro is Chovav, and therefore, he needs to say that Yitro traveled back and forth,7 going home in the first year but returning in the second year. Chizkuni 18:13 and Peirush HaRosh Shemot 18:4 also assume that Chovav and Yitro are the same person, but they offers a Pesikta based alternative that Moshe sent Yitro away only temporarily so that he would not be present for the revelation at Sinai, and that Yitro returned to the Israelite camp immediately after the Decalogue.
Mekhilta DeRabbi Yishmael – Vayishma (18:1) and Vayshalach (18:27) – Reconstructing R. Yehoshua's position is complicated by the textual variants of two different passages in the Mekhilta DeRabbi Yishmael, each of which records a dispute between R. Yehoshua and R. Elazar HaModai.
  • The first passage records a dispute over when Yitro came. According to the Oxford and Munich manuscripts of the Mekhilta Yitro Amalek 1 it would seem that R. Yehoshua claims that Yitro embarked on his journey only after hearing about the revelation at Sinai, while R. Elazar HaModai argues that he heard about the splitting of the sea. However, from various other textual witnesses8 it appears that these two manuscripts are missing a section (possibly the result of a homeoteleuton) and R. Yehoshua asserts that Yitro came after hearing of the victory over Amalek,9 while it is R. Elazar HaModai who maintains that he came after hearing about the revelation at Sinai.10
  • The second passage in Mekhilta DeRabbi Yishmael Yitro Amalek 2 discusses their opinions regarding the meaning of the intensive (piel) form of "vayshalach" in 18:27 (which might imply that Moshe purposefully sent Yitro away rather than merely letting him depart). Here, R. Yehoshua enigmatically explains that Moshe sent Yitro away "with the glory of the world" ("בכבודו של עולם"). This leads some to explain based on the variant "from the glory of the world" ("מכבודו של עולם") found in Yalkut Shimoni Yitro 271, that R. Yehoshua, like the Pesikta, contends that Yitro was sent away so that he would not be present for the revelation. Accordingly, R. Yehoshua would maintain that all of Chapter 18 occurred before the Decalogue.11
Midyan and Mount Sinai – While the exact geographical locations of Midyan or Mount Sinai are unknown, from the fact that Moshe tended to Yitro's flock at Mount Sinai (Shemot 3:1) it would appear that they were in close enough proximity for Yitro to have heard the news of the Exodus in Midyan and still arrive with plenty of time before the revelation at Sinai two months later.12
"Before God"(18:12) – If Yitro and Moshe met at Rephidim, these words could mean either at a sacrificial altar or at Moshe's personal tent where he would communicate with Hashem. If they met at Mount Sinai, the words could also refer to Mount Sinai itself. See here for elaboration.
"The statutes of God and His laws"(18:16) – this term would refer to commandments given before the Decalogue, either ad hoc or at Mara. See Statutes Before Sinai and Mitzvot at Marah for elaboration.

In the 3rd Month

Yitro came in the beginning of the third month (of the first year) immediately after the nation's arrival at Mount Sinai, but before the preparations for the giving of the Decalogue in the rest of Chapter 19.

"At God's mountain"(18:5) – Josephus can interpret this phrase simply, as Moshe and the nation were already encamped at Mount Sinai when Yitro arrived. See also Antiquities 2:12:1 (265) and 3:5:1 (76) where Josephus says that Mount Sinai was known to have a Divine presence even before Hashem's revelation to Moshe and the nation.14
Chronology – According to Josephus, only the first two verses of Chapter 19 are not in chronological order, as they transpired before Yitro's arrival. Josephus can easily explain this limited achronology by saying that these two verses introduce the revelation at Sinai, and their placement at the beginning of Chapter 19 is for literary and thematic reasons.
Josephus vs. Pesikta et al. – The approach of Josephus is very close to that of the Pesikta. According to both, all of Chapter 18 took place before the Decalogue. They differ only with regard to the exact time and place of the events. According to the Pesikta, the events of Chapter 18 happened at the end of the second month in Rephidim, while according to Josephus they occurred at the beginning of the third month at Mount Sinai.
Dating the Decalogue – Josephus is able to adopt his approach only because he gives no date for the revelation at Mount Sinai – see here for elaboration. Had he assumed (like most traditional commentators) that the Decalogue was given on the 6th or 7th of Sivan and that all of the events of Chapter 19 transpired during the first six or seven days of Sivan, he would not have been able to also fit all of the events of Chapter 18 into this packed schedule.15
"Before God"(18:12) – According to Josephus, these words refer to the burning bush on Mount Sinai. See here for elaboration.
"The statutes of God and His laws"(18:16) – this must refer to commandments given before the Decalogue. See Statutes Before Sinai and Mitzvot at Marah for elaboration.
Midyan and Mount Sinai – Josephus maintains that Midyan and Mount Sinai were geographically close – see Antiquities 2:12:1 (265).
Shemot 18 and Devarim 1 – This position can maintain either that "at that time" in Devarim 1:9 refers to the first year, or that Shemot 18 and Devarim 1 refer to different appointments.
Chovav the son of Reuel in Bemidbar 10 – Josephus would most likely maintain that Chovav is not Yitro, as he identifies Reuel (Chovav's father) with Yitro – see Antiquities 2:12:1 (264) (and see Yitro's Names).

All Achronological

All of Chapter 18 occurred after the Decalogue, and the entire chapter is NOT in its chronological place ("אין מוקדם ומאוחר בתורה"). This position also subdivides into two:

Before the building of the Tabernacle

All of Chapter 18 happened after the Decalogue, but before the completion of the Tabernacle.

"At God's mountain"(18:5) – Moshe and the nation were already encamped at Mount Sinai when Yitro arrived "at God's mountain" in 18:5.
"The statutes of God and His laws"(18:16) – This is readily understood as the story takes place after the revelation at Mount Sinai. See Statutes Before Sinai and Mitzvot at Marah for elaboration. This is particularly important for Rashbam who does not think that the nation received laws already at Mara (see his commentary to Shemot 15:25).
Date of Yitro's arrival – According to this position, it is unclear exactly when Yitro arrived, as Moshe was occupied at Mount Sinai in the months after the Decalogue (see also Rashbam Shemot 24:1).
  • One possibility is that Yitro arrived only after Moshe descended with the second set of tablets. See the position cited by Chizkuni 18:27 that Yitro arrived on Yom HaKippurim of the first year, and cf. Rashi and Tosafot below who, despite maintaining that Yitro arrived earlier, posit that Yitro observed Moshe judging the people on the day after Yom HaKippurim.
  • Alternatively, Yitro might have come during the second set of forty days after the Decalogue, if one assumes that Moshe spent those days in his personal tent and not on the mountain [see here for the various positions on this issue]. This variation creates the intriguing possibility that "the tent" in 18:6 refers to the same tent of Moshe described in Shemot 33:7-11 (cf. Hoil Moshe Shemot 18:7), and that the people coming to "inquire of God" in 18:15 are the same people "seeking out Hashem" in 33:7.
Chronology – This approach needs to explain why this story is not written in its chronological place. According to Rashbam, the Torah places it here in order not to break up the continuity of the legal section which follows with an unrelated narrative. This, however, raises the question as to why the Torah did not place the Yitro story after Shemot 34. Chizkuni 18:27 offers an alternative that the story is connected by its opening to the Exodus and by its ending to the giving of the Torah.Chronological and Thematic Order.
Date of Yitro's departure and relationship to Devarim 1 – This position can maintain either that "at that time" in Devarim 1:9 refers to the first year, or that Shemot 18 and Devarim 1 refer to different appointments. A variation of this position is given by R. Elazar HaModai in Mekhilta DeRabbi Yishmael Yitro Amalek 1, and is developed by Chizkuni 18:27. This variation also holds that Yitro arrived only after the Decalogue, but it differs in that it asserts that Yitro departed only in the second year (see above for R"E HaModai's interpretation of "vayshalach"). In light of this, Chizkuni maintains that the appointments of Shemot 18 and Devarim 1 are one and the same and took place in the second year.16
"Before God"(18:12) – These words can refer to Mount Sinai itself, a sacrificial altar, or Moshe's personal tent. See here for elaboration.
Chovav in Bemidbar 10 – Rashbam Bemidbar 10:29 who identifies Chovav with Yitro (see Yitro's Names), can say either that Yitro stayed until the second year and then returned home or that Yitro journeyed back and forth. R"E HaModai and Chizkuni also identify Yitro with Chovav, but they say that Yitro=Chovav departed only once in the second year. Rambam could simply maintain that Chovav is not Yitro.
According to R. Elazar HaModai in the Mekhilta DeRabbi Yishmael, Yitro came because he heard about the revelation at Mount Sinai.17 However, Ramban points out that the verse says that Yitro heard only about the Exodus, but does not mention Mount Sinai.18
Midyan and Mount Sinai – For unknown reasons, R. Avraham b. HaRambam posits that Mount Sinai is very far from Midyan, and thus fifty days would not have given Yitro enough time to receive reports of the Exodus and still arrive before the Decalogue.19

After the building of the Tabernacle

All of Chapter 18 took place only in the second year after the Tabernacle was already built.

"Where he was encamped at God's mountain"(18:5) – Ibn Ezra 18:5 explains that the verse comes to tell us that Moshe and the nation were already encamped at Mount Sinai for a long time before Yitro arrived.
"Before God"(18:12) – Both R. Saadia and Ibn Ezra explain that these words refer to the Tabernacle. See here for a discussion of other verses in Tanakh.
"The statutes of God and His laws"(18:16) – these words present no problem since the story takes place after many commandments were already given. See Statutes Before Sinai and Mitzvot at Marah for elaboration.
Shemot 18 and Devarim 1 – According to Ibn Ezra, Shemot 18 and Devarim 1 describe the same appointment of judges, which took place in the second year. This fits with the context of Devarim 1 and the words "at that time" in Devarim 1:9.
Delayed reaction – As 18:1 states that Yitro came after hearing about the Exodus, it is difficult to understand why he would have waited a year before coming.
Achronology – This approach maintains that Shemot 18's chronological place should have been the book of Bemidbar. It must therefore grapple with why the Torah placed this story in a different book in the midst of a unit chronicling a national journey (see Context) which happened almost an entire year earlier. Ibn Ezra, Radak, Tosafot Avodah Zarah 24b "Yitro", and Cassuto suggest that the Torah wanted to juxtapose the story of Yitro with the story of Amalek that precedes it – see here for elaboration of the connections between the stories.21 In contrast, Ralbag proposes that the Torah's order links the Yitro story with the following story of the Decalogue. According to him, Yitro's affirmation of his belief in Hashem parallels the entire nation's belief in Hashem which is what allowed for the revelation at Sinai. For other examples, where homiletical concerns lead to achronological recounting of events see Chronological and Thematic Order.
Chovav in Bemidbar 10 – Ibn Ezra and Radak maintain that Yitro is Chovav, and that Shemot 18 and Bemidbar 10 describe the same visit of Yitro. According to them, Yitro came only once, and then returned to his own land.
Sacrifices before Sinai – R. Saadia states that "peace offerings" (שלמים) were not offered before the revelation at Sinai, and thus Yitro's sacrifices in 18:12 were brought only afterwards. There are two conflicting opionions on this matter in Yerushalmi Megillah 1:11 and Bavli Zevachim 116a. See here regarding sacrifices before Mount Sinai. R. Saadia (like the Bavli) assumes that the sacrifices were offered on the day Yitro arrived, and thus Yitro's entire visit came only after the Decalogue (Cf. the second possibility in Ramban Shemot 18:12 cited below).
Aharon and Chur's task – Ibn Ezra in both of his commentaries to Shemot 24:14 explains that when Moshe was on Mount Sinai, Aharon and Chur were designated to judge the people. He notes that this was necessary because Yitro came (with his advice) only in the second year (cf. Ramban and Abarbanel below, and see R. Isaac Reggio Shemot 18:24 who adduces this verse as a proof for Ibn Ezra's position).

Chronological Compromise

Chapter 18 combines six events which happened during different time periods, and part of Chapter 18 is in its chronological place while part is not. There is a full spectrum of variations of this compromise position:22

Only Yitro's departure was after the revelation at Sinai

Almost the entire chapter (18:1-26) transpired before the nation arrived at Mount Sinai, and only the last verse (18:27) regarding Yitro's departure is achronological and happened later.

Sources:ShadalShemot 18:1About Shadal in his first possibility,23 possibly RambanShemot 18:1Shemot 18:12Shemot 24:14About Ramban in his main possibility.24
Chronology – This opinion is consistent with Ramban's view that the Torah is generally in chronological order, with Shadal adding that the single verse achronology of Yitro's departure is caused by a desire to complete the story.25 This position can also readily explain why Chapter 18 appears in its place despite the fact that it interrupts a unit detailing the nation's sojourns from Yam Suf to Sinai (see Context).
Yitro at Sinai – Ramban 18:1 suggests that Yitro came to Mount Sinai because he knew from Moshe about the impending revelation.26 For this reason, Ramban (in contrast to the Pesikta et al.) postpones Yitro's departure until after the Decalogue and posits that there is a limited achronology with regard to this one verse.
"The statutes of God and His laws"(18:16) – Shadal says that this verse speaks of commandments that were given to Moshe on an ad hoc basis ("להוראת שעה") before the revelation at Sinai. See Statutes Before Sinai and Mitzvot at Marah.
Shemot 18 and Devarim 1 – Ramban (Shemot 18:1, Devarim 1:9,18) maintains that both stories describe the same appointment of judges – see here, and thus the account in Devarim must also be speaking about the first year. However, the context in Devarim 1 is the events of the second year. Ramban therefore needs to explain that the phrase "at that time" in Devarim 1:9 does not imply that the judicial appointments occurred at the same time as the rest of the events of that chapter, but rather a year prior to them.27 Ramban (Devarim 1:18) also encounters difficulties in trying to explain why Devarim 1 makes no mention of Yitro. In contrast, Shadal does not address the relationship between the story here and in Devarim, and he could maintain that Devarim 1 is a retelling, not of the story of Shemot 18, but rather of the story in Bemidbar 11.28
Chovav in Bemidbar 10 – Ramban and Shadal both agree that Yitro and Chovav are the same person, but they disagree as to how many visits he made and what ultimately became of him. Ramban thinks that Yitro converted,29 and he consequently assumes30 that Yitro/Chovav acceded to Moshe's request to remain with the Children of Israel (see Did Yitro Ever Return). Therefore, Ramban says that Yitro traveled back and forth,31 going home in the first year to convert his family,32 but returning in the second year and ultimately remaining with the nation. According to Shadal, however, Yitro/Chovav arrived in the first year, remained until the second year but did not convert (see here), and left when the Children of Israel left the area of Mount Sinai33 to begin their journey to the land of Israel. According to him, Shemot 18:27 describes the same departure of Yitro which happened only in Bemidbar 10:29, in the second year.
"Before God" – Shadal explains that this refers to partaking from the sacrifices mentioned at the beginning of the verse.
"At God's mountain"(18:5) – According to Ramban, this phrase does not describe where the nation was camped, but rather where Yitro initially stopped on his way to visit Moshe.34 From there he sent messengers to Rephidim to inform Moshe of his imminent arrival. Moshe then traveled to Mount Sinai to greet him, and they apparently returned together to Rephidim where Yitro observed Moshe judging the people – see Ramban Shemot 17:5 and 18:1 that Rephidim and Mount Sinai were only a short distance apart.35 Shadal does not explicitly address the contradiction between "at God's mountain" in 18:5 and the nation arriving only in verse 19:2.
Aharon and Chur's task – Ramban Shemot 24:14 explains that when Moshe ascended Mount Sinai, Aharon and Chur were assigned to deal only with the matters that were too difficult for the regular judges. This is consistent with his approach that judges were appointed already before the Decalogue (cf. Ibn Ezra above and Abarbanel below).

Yitro's advice was implemented after the revelation at Sinai

Yitro arrived and also gave his advice (18:1-23) before the people came to Mount Sinai, but Moshe appointed the judges and Yitro departed (18:24-27) only in the second year when they left Mount Sinai.

Why did Moshe need Yitro's advice – Akeidat Yitzchak and Abarbanel attempt to address the question of why Moshe on his own had not already implemented Yitro's plan. By assigning the advice and its eventual implementation to two different time periods, they are able to explain that the timing was not yet ripe for Yitro's plan.36 This allows them to posit that Moshe was always planning to appoint judges, but that it was first necessary for the people to receive the laws.37
"At God's mountain"(18:5) – According to Abarbanel, even though some of the people were still at Rephidim until Chapter 19, Moshe and part of the nation38 were at Mount Sinai already from Chapter 17 onwards.39 Abarbanel also notes that Hashem had instructed Moshe to draw water from the rock at Horev in 17:6, and that Sinai was the "hill" (17:9) where Moshe sat during the battle with Amalek (like Ibn Ezra there). Thus, we can readily understand why in 18:5 Yitro came to "where he (Moshe) was encamped, at God's mountain." Abarbanel adds that we should not be surprised that the Torah calls Mount Sinai "God's mountain" even before the Decalogue (see also Shemot 3:1), because the Torah uses the names by which places were later known ("על שם סופו"). This suggestion appears already in Sifre Devarim 22 (cf. Targum Onkelos Shemot 3:1, 18:5). Alternatively, R. D"Z Hoffmann 18:5 cites an opinion that "God's mountain" refers not to Mount Sinai, but rather to the mountain upon which Hashem appeared and provided water in Shemot 17:6.40
"Before God" – Akeidat Yitzchak and Abarbanel explain these words as in front of the altar which Moshe had built. Abarbanel identifies this altar as the one Moshe built at the culmination of the battle with Amalek in 17:15.
"The statutes of God and His laws"(18:16) – Akeidat Yitzchak and Abarbanel both explain that these refer to commandments given at Mara, however they diverge as to the relationship between these and the laws of Parashat Mishpatim. According to the Akeidat Yitzchak, the people only received some basic civil laws at Mara, and therefore Moshe needed to adjudicate every single dispute until the people received the rest of the laws in Parashat Mishpatim. In contrast, Abarbanel posits that Moshe received all of civil law at Mara, but that it was not until Parashat Mishpatim, that Moshe was instructed to transmit the laws to the people, and thus in the meantime Moshe needed to judge every case. Abarbanel does not explain why Moshe could not have instructed the people already at Mara, and thereby have avoided the unmanageable workload. For more, see Statutes Before Sinai and Mitzvot at Marah.
Shemot 18 and Devarim 1 – All of the above commentators maintain that the stories of the appointment of judges in Shemot 18 and Devarim 1 are one and the same event which occurred in the second year. This both matches the context of Devarim 1, and squares nicely with the verbatim parallels between Shemot 18 and Devarim 1 – see Moshe's Assistants. However, as a result, this position must grapple with the question of why Moshe would have waited until the second year to appoint the judges, if the laws were already transmitted to the people in the first year.41 Alternatively, a variation of this approach could avoid this problem by dating the implementation of Yitro's advice to later in the first year (immediately after the receipt of the laws of Parashat Mishpatim) and saying that Devarim 1 incorporates flashbacks to the first year.
Relationship to Bemidbar 11 – Given their dating of Shemot 18:24-26 to the second year, these commentators could go one step further and integrate the judicial and administrative appointments of Shemot 18, Bemidbar 11, and Devarim 1 into one story. See Moshe's Assistants for further analysis.
Aharon and Chur's task – Abarbanel Shemot 24:14 proposes that when Moshe was away on Mount Sinai, there was a need for a two-tierred system. The responsibility for judging the simple matters (in place of Moshe) was given to the seventy elders, while the difficult cases were assigned to Aharon and Chur. This is consistent with his position that permanent judges were not appointed until the second year (cf. Ramban and Ibn Ezra above).
Chovav in Bemidbar 10 – This position maintains that Yitro came in the first year but departed only in the second year, and Bemidbar 10 is speaking about the same departure of Yitro mentioned in the final verse of our chapter.
Chronology – Despite Moshe's implementation and Yitro's departure taking place only after the Decalogue, they are recorded here in order to complete the story. See here for other examples.
Moshe's family at Sinai – According to the Akeidat Yitzchak it is inconceivable that Moshe's wife and sons would not have been present for the revelation at Mount Sinai (cf. Tur and Tosafists above).

Yitro gave his advice only after the revelation at Sinai

Yitro arrived and offered sacrifices (18:1-12) before the Decalogue, but he gave his advice (18:13-27) only afterwards.

"The statutes of God and His laws"(18:16) – these words present no problem for this position since Yitro's advice takes place after the commandments were given. For more, see Statutes Before Sinai.
Chronology – The Tosafists in Avodah Zarah 24b "Yitro" explain that the Torah places the second half of the chapter achronologically in order to complete the Yitro unit (see the second possibility in Ramban 18:12 below who explains similarly).
This option also appears to be the likely reconstruction of Rashi's position. In explaining Moshe's judging of the people "on the next day" (18:13), Rashi cites a Sifre (a reference to our Mekhilta DeRabbi Yishmael Yitro Amalek 2) that this was the day after Yom HaKippurim.42 From here it is clear that Rashi is of the opinion that the second half of Chapter 18 occurred after the Decalogue.43
If Yitro observed Moshe on the day after Yom HaKippurim, one can readily understand that Moshe had a huge backlog of cases to judge because he had been away on Mount Sinai for the previous four months. See Why So Many Litigants for more.
Rashi's position regarding the first half of Chapter 18 is somewhat ambiguous. Rashi on 18:1 and 18:8 presents the opinion in the Mekhilta DeRabbi Yishmael that the events which Yitro heard about and which Moshe recounted to him were only the ones which occurred before the revelation at Sinai.44 It would appear from here that Rashi is taking the position that Yitro arrived before the Decalogue, and that the reason Yitro was not told about the Decalogue was that it had not yet happened.45
"On the next day"(18:13) – If Rashi holds that the first half of Chapter 18 took place before the Decalogue, then he is in effect saying that there is a disconnect between the two halves of Chapter 18, and "it happened on the next day" in 18:13 cannot mean that Moshe judged the people on the very next day after the events of 18:1-12. And, in fact, Rashi says that this phrase refers to "the next day after Moshe's descent from the mountain," and not to the day after the meal described in 18:12. See also Ramban who, in reinterpreting the Mekhilta DeRabbi Yishmael, argues that it is impossible to say that 18:13 took place on the day after Yom HaKippurim if it were also the day after the events of the previous verses, because then the meal in 18:12 on the day before would have violated the prohibition of eating on Yom HaKippurim (cf. Tosafot HaShalem 18:13:6).
R. Eliyahu Mizrachi disagrees with Ramban. He argues that nothing prevented having a meal on Yom HaKippurim, as the commandment to fast had not yet been received. He also points out that while "מחר" could refer to any time in the future, "ממחרת" always refers to the very next day. Accordingly, Rashi could maintain that both halves of Chapter 18 took place after the Decalogue, and that 18:13 took place on the day after the feast in 18:12 which was on Yom HaKippurim. This is supported by Rashi's mention of the Torah already in his interpretation of 18:9 (see note above). See also Minchah Belulah.
Chovav in Bemidbar 10 – Rashi Shemot 18:13 asserts both that Yitro and Chovav are one and the same, and also that there is no hint that Yitro traveled back and forth. Thus, he brings this as a proof that the departures of Yitro in Shemot 18 and Chovav in Bemidbar 10 must be referring to the same event which took place in the second year.
Shemot 18 and Devarim 1Rashi Devarim 1:15 implies that Devarim 1 describes the implementation of Yitro's advice – see Appointing Moshe's Assistants.
Aharon and Chur's task – Rashi Shemot 24:14 explains that Aharon, Chur, and the seventy elders judged the people while Moshe was on Mt. Sinai. This is in accordance with his view that Yitro's advice was implemented only in the second year. Similarly, Rashi Shemot 18:18 (Cf. Mekhilta DeRabbi Yishmael) implies that Yitro's judges were intended to supplement the existing system which already included Aharon, Chur, and the seventy elders.46

Yitro offered sacrifices only after the revelation at Sinai

Yitro arrived (18:1-11) before the revelation at Sinai, but he brought sacrifices and gave his advice (18:12-27) only afterwards.

Sacrifices before Sinai – This suggestion is Ramban's attempt to reconcile his own favored position that Yitro arrived before the Decalogue with the opinion in Bavli Zevachim 116a that "peace offerings" (שלמים) were not offered before the Decalogue.
Did Yitro convert? According to Ramban, Yitro converted, and verse 12 speaks of his conversion ceremony sacrifices.
Chronology – Ramban explains that the Torah places the second half of the chapter achronologically in order to complete the Yitro unit (see the Tosafists above who explain similarly).
Yitro at Sinai – See above for Ramban's position that Yitro came to Mount Sinai because he knew about the upcoming revelation. Similarly, the Minchah Belulah 18:5 states explicitly that Yitro's purpose in coming was to be present for the revelation, and thus he brought his own wife and children along, in addition to Zipporah and her sons (see here for elaboration).48 In 18:13, he explains, like R"E Mizrachi, that Yitro's sacrifices and the meal took place on Yom HaKippurim, and that there was no fast that year because they received the second set of tablets (similar to the Yom HaKippurim in the year Shelomo built the Temple). The Minchah Belulah Bemidbar 10:29 identifies Yitro with Chovav but it is not clear if he thinks that Yitro stayed until the second year or made two trips.49
"On the next day"(18:13) – This possibility must claim that there is a long interim period between Yitro's reunion with Moshe and his sacrifices. However, the Torah gives no indication of such, and the words "And it happened on the next day" in verse 13 would seem to imply that the prior events all occurred on the same day. See above that R. Saadia explicitly disagrees with this possibility of Ramban.

Yitro arrived only after the revelation at Sinai

Yitro heard the news of the Exodus (18:1) before the revelation at Mount Sinai, but he arrived at the camp only afterwards.

Sources:A possibility raised by RambanShemot 18:1About Ramban.50
This position is a variation of the opinion of Rashbam / R. Elazar HaModai in the Mekhilta DeRabbi Yishmael. According to Ramban, this variation has the advantage of being able to explain why the Torah doesn't say that Yitro heard already in Midyan about the revelation at Sinai (see above for alternative explanations).
Chronology – According to this, the first verse of the chapter is in chronological order, and the rest of the chapter appears achronologically in order to complete the story.51
An alternative split between hearing the news and the rest of the chapter could be that Yitro heard the news of the Exodus before the battle with Amalek, but arrived only after the battle. In this case, the chronological place of 18:1 would be before Chapter 17, and perhaps even before Chapter 16.