In the composite text that we now call “the Bible” there are two places in the narrative where Moses’ father-in-law returns to his land: Exodus 18:27 and Numbers 10:29-30, before and after Sinai respectively. In the same manner that we saw in the two previous entries (#125 & #127), these two stories are doublets. Both passages speak of Moses’ father-in-law’s departure back to his land. However, as we’ve already seen (#85) both of these textual traditions preserve a different name for Moses’ father-in-law. Jethro is the hallmark of the Elohist tradition, while Reuel, or here Hobab, that of the Yahwist.
The selection of the judges in Exodus 18 also stands in sharp contradiction to the same account in Deuteronomy 1. However we will look at all the Deuteronomic contradictions together when we get to the book of Deuteronomy some time in the Fall, I imagine.
Tomorrow we will start to examine the Sinai pericope, Exodus 19-24. Chapters 19 and 24 are notoriously difficult for source critics. There seems to be a number of traditions, maybe even expansions, assembled together in these chapters. Exodus 20-23 is mostly of the Elohist source and it is the oldest of the three law codes now contained in the Pentateuch.
The only other JE material in the book of Exodus is chapters 32-34, where we will encounter the Golden Calf narrative and a second Ten Commandment tradition.
Excluding Exodus 32-34, all of Exodus 25 to Numbers 10:28, including the entire book of Leviticus, is from P. If you haven’t done so yet, I highly recommend becoming acquainted with the aims and themes of the Priestly writer.