In my post Did Jesus ascribe the entire Torah to Moses? I discuss some of the evidence that the book of Genesis contains anachronisms evidencing that the Torah has been redacted over time, in spite of protestations to the contrary by some, especially those within the conservative Protestant camp. Discussing the evidence for a Davidic-Solomonic redaction of Genesis, Gary Rendsburg, admitting that the evidence is overwhelming that “[Not] all of Genesis of the work of one author, for there clearly remain different sources and variant traditions” (p. 106), notes some of these anachronisms that makes no sense in light of purely Mosaic authorship:
The relationship between Jacob and Esau in Genesis is plainly a reflection of Israelite-Edomite affairs during the early monarchy. The oracle to Rebekah that of the two sons "the older shall serve the younger" (25:23), and the blessing of Isaac to Jacob, "you shall be your brothers' master" (27:29), describes Israel's subjugation of Edom under David (2 Sam 8:14). Isaac's words to Esau, "you shall throw off his yoke from your neck" (27:40), refer to the Edomite revolt at the end of Solomon's reign (1 Kgs 11:14-25).
Jacob and Esau are depicted as twins, which is significant in that there appears to have been a closer link between Israel and Edom than, by comparison, between Israel and other nations conquered by David. 2 Sam 8:2 and 8:6 mention tributary exacted from Moab and Aram-Damascus respectively and thus we infer that their kings were allowed to rule as subjects of David. 2 Sam 12:30 states that David merely took the actual crown from the king of Ammon, but it does not imply that the Ammonite king was ousted. In contrast we have reference to the incorporation of Edom as an Israelite province under David (2 Sam 8:14), and of the flight of Edomite royalty to Egypt at the time of the conquest (1 Kgs 11:14-18). The rule of David and Solomon over Edom was firmer, thus Edom was considered more closely linked to Israel, and thus Jacob and Esau are pictured as twins.
The other countries just mentioned also appear in Genesis. Moab and Ammon occur in 19:37-38, where they are genealogically linked to the family of Abraham. This too implies a connection with Israel, and we are to see here a reflection of Davidic-Solomonic rule over the two countries (2 Sam 8:2; 10:6-14). Aram appears throughout the patriarchal stories but the one occurrence which most likely mirrors events of the Davidic period is the agreement between Laban, the Aramean, and Jacob, eponymous ancestor of Israel, at Gilead in 31:45-54. The peaceful resolution of an Aramean-Israelite conflict in the general area of Gilead occurs in 2 Sam 10:19, thus prompting the link between the two episodes.
Returning to Edom, for a moment, we naturally should refer to 36:1-43 with its detailed material on Esau's descendants and the Edomite kings. Such a list, most certainly of Edomite origin or at least based on material of Edomite origin, would have been incorporated into Israelite literature at a time when Israel had domain over Edom, again during the Davidic-Solomonic empire. Furthermore, 36:31 (these are the kings who reigned in the land of Edom before a king reign over the Israelites") suggests that the list originates from the period of the early monarchy. If it were known from an earlier period, such a statement would be impossible. If it were from a later period, we would expect an Edomite king list beyond that of the time before 1000, i.e., "before a king reign over the Israelites." (Gary A. Rendsburg, The Redaction of Genesis [Winona Lakes, Ind.: Eisenbrauns, 1986], 108-10)
