16 So it happened, when all the men of war were consumed and dead from among the people, 17 that Yahweh spoke to me, saying, 18 “You are this day to pass over Ar, the border of Moab: 19 and when you come near over against the children of Ammon, don’t bother them, nor contend with them; for I will not give you of the land of the children of Ammon for a possession; because I have given it to the children of Lot for a possession.” 20 (That also is accounted a land of Rephaim: Rephaim lived therein before; but the Ammonites call them Zamzummim,
Matthew Henry's Commentary on Deuteronomy 2:16-20
Commentary on Deuteronomy 2:8-23
(Read Deuteronomy 2:8-23)
We have the origin of the Moabites, Edomites, and Ammonites. Moses also gives an instance older than any of these; the Caphtorims drove the Avims out of their country. These revolutions show what uncertain things wordly possessions are. It was so of old, and ever will be so. Families decline, and from them estates are transferred to families that increase; so little continuance is there in these things. This is recorded to encourage the children of Israel. If the providence of God has done this for Moabites and Ammonites, much more would his promise do it for Israel, his peculiar people. Cautions are given not to meddle with Moabites and Ammonites. Even wicked men must not be wronged. God gives and preserves outward blessings to wicked men; these are not the best things, he has better in store for his own children.