The Israelites regarded the Edomites as close relatives, even more closely related to them than the Ammonites or Moabites. Specifically, they identified the Ammonites and Moabites as descendants of Lot, Abraham's nephew, but the Edomites as descendants of Esau, Jacob's brother (Genesis 19:30-36; Genesis 36:1). Thus Edom occasionally is referred to as a “brother” to Israel (Amos 1:11-12). Edomites seem not to have been barred from worship in the Jerusalem Temple with the same strictness as the Ammonites and Moabites (Deuteronomy 23:3-8). Yet, as is often the case with personal relations, the closest relative can be a bitter enemy. According to the biblical writers, enmity between Israel and Edom began already with Jacob and Esau (when the former stole the latter's birthright) and was exacerbated at the time of the Israelite Exodus from Egypt (when the Edomites refused the Israelites passage through their land). Be that as it may, much of the conflict also had to do with the fact that Edom was a constant threat to Judah's frontier, and moreover blocked Judean access to the Gulf of Aqaba.

Verse 31
By degrees the Edomites worked out the Horites, and got full possession of the country. 1. They were ruled by kings who governed the whole country, and seem to have come to the throne by election, and not by lineal descent: these kings reigned in Edom before there reigned any king over the children of Israel - That is, before Moses's time, for he was king in Jeshurun. God had lately promised Jacob that kings shall come out of his loins: yet Esau's blood becomes royal long before any of Jacob's did. Probably it was a trial to the faith of Israel, to hear of the power of the kings of Edom, while they were bond-slaves in Egypt: but those that look for great things from God must be content to wait for them. God's time is the best time. 2. They were afterward's governed by dukes again, here named, who, I suppose, ruled all at the same time in several places in the country. They set up this form of government, either in conformity to the Horites, who had used it, Genesis 36:29, or God's providence reduced them to it, as some conjecture, to correct them for their unkindness to Israel, in refusing them passage through their country, Numbers 20:18.

Verse 43
Mount Seir is called the land of their possession - While the Israelites dwelt in the house of bondage, and their Canaan was only the land of promise, the Edomites dwelt in their own habitations, and Seir was in their possession. The children of this world have their all in hand, and nothing in hope, while the children of God have often their all in hope, and next to nothing in hand. But, all things considered, it is better to have Canaan in promise than mount Seir in possession.