The children of Reuben and the children of Gad. Reuben and Gad had both been camped on the same (southern) side of the tabernacle, but had not apparently been neighbours, since Simeon intervened on the march (see on Numbers 2:10-14).
Simeon, however, was at this time enfeebled and disgraced, and was not likely to assert himself in any way. The "great multitude of cattle" belonging to the two tribes probably point to pastoral habits of long standing, since the cattle of the Amorites and Midianites would be equally divided among all.
The land of Jazer. Jazer, or Jaazer, probably stood near the northern source of the Wady Hesban, which enters the Jordan not far from its mouth. The "land of Jazer" would seem to mean the Mishor, or plateau, of Heshbon, over which the Israelites had passed on their way to the plains of Moab (see on Deuteronomy 3:10, "all the cities of the Mishor").
The land of Gilead. Gilead as the name of a district only previously occurs in Genesis 37:25. It is used with a considerable latitude of meaning in this and the following books. In its widest sense it stands for the whole territory to the east of Jordan (see on Genesis 37:26, Genesis 37:29), including even the rugged, volcanic districts of Bashan (Deuteronomy 34:1; 1 Chronicles 5:16); but more properly it denoted the lands on both sides the Jabbok, from the Wady Hesban on the south, to the Yermuk and lake of Tiberias on the north, now known as the provinces of Belka and Jebel Ajlun.
These lands are by no means uniformly flat, as the name "Mount Gilead" testifies, but include mountains and hills covered with fine open forests of oak (cf. 2 Samuel 18:8, 2 Samuel 18:9) as well as rolling downs and treeless plains.
The soil is almost everywhere of great fertility, and the water supply, although very scanty in summer, is sufficient if carefully husbanded. Even now these provinces produce great store of grain, and are depastured by vast flocks of sheep.
In Roman times, as the innumerable ruins testify, they were filled with a large and opulent population. Indeed there could be no comparison in point of agricultural and pastoral value between these open and fertile lands and the broken, stony country of Southern Palestine.
If they ever enjoy again the blessing of a strong government and continuous peace they will again justify the choice of Reuben and Gad. A place for cattle. מָקוֹם is used here in the broader sense of district (cf.
Genesis 1:9), and is equivalent to אֶרֶץ in Genesis 37:4.