Ar, the chief city of the Moabites, Numbers 21:15,28, here put for the whole country, which depended upon it. The children of Lot; so called to signify that this preservation was not for their sakes, for they were a wicked people; but for Lot's sake, whose memory God yet honours.
Related Commentaries of Deuteronomy 2:9
Deuteronomy 2:9
9 And the LORD said unto me, Distressb not the Moabites, neither contend with them in battle: for I will not give thee of their land for a possession; because I have given Ar unto the children of Lot for a possession.