The children of Gad built - Aroer - This was situated on the river Arnon, Deuteronomy 2:36; 2 Kings 10:33. It was formerly inhabited by the Emim, a warlike and perhaps gigantic people. They were expelled by the Moabites; the Moabites by the Amorites; and the Amorites by the Israelites. The Gadites then possessed it till the captivity of their tribe, with that of Reuben and the half of the tribe of Manasseh, by the Assyrians, 2 Kings 15:29, after which the Moabites appear to have repossessed it, as they seem to have occupied it in the days of Jeremiah, Jeremiah 48:15-20.
The cities here named fall into three groups. On Dibon, compare Numbers 21:19. The Moabite stone was discovered here in 1868. This city, occupied on the first acquisition of the territory by the Gadites, and assigned by Joshua to the Reubenites, was eventually recaptured by the Moabites, in whose hands it remained. Ataroth, i. e., “crowns” (Attarus?) was seven miles northwest of Dibon. Aroer (Arair) lay between Dibon and the Arnon.
Atroth, Shophan - , was Atroth-Shophan, i. e., Atroth, or Ataroth of Shophan, or “of the burrow;” thus distinguished from the Ataroth named in the verse preceding from which it was probably not far distant. These four cities may be styled the Dibon settlement.
Numbers 32:35
Jaazer - (compare Numbers 32:1) with the neighboring “Jogbehah” (Jebeiha), seven miles to the northeast, formed the second group.
Numbers 32:36
The third Gadite settlement lay in the valley of the Jordan, to the west of the preceding. It comprised the cities of Bethnimrah (Nimrun) and “Beth-haran” (Beit-ha-ran).