A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
num 32:1THE REUBENITES AND GADITES ASK FOR AN INHERITANCE. (Num. 32:1-42)
the land of Jazer, and the land of Gilead--A complete conquest had been made of the country east of the Jordan, comprising "the land of Jazer," which formed the southern district between the Arnon and Jabbok and "the land of Gilead," the middle region between the Jabbok and Jarmouk, or Hieromax, including Bashan, which lay on the north of that river. The whole of this region is now called the Belka. It has always been famous for its rich and extensive pastures, and it is still the favorite resort of the Bedouin shepherds, who frequently contend for securing to their immense flocks the benefit of its luxuriant vegetation. In the camp of ancient Israel, Reuben and Gad were pre-eminently pastoral; and as these two tribes, being placed under the same standard, had frequent opportunities of conversing and arranging about their common concerns, they united in preferring a request that the trans-jordanic region, so well suited to the habits of a pastoral people, might be assigned to them.
num 32:6Moses said unto the children of Gad and to the children of Reuben, Shall your brethren go to war, and shall ye sit here--Their language was ambiguous; and Moses, suspicious that this proposal was an act of unbelief, a scheme of self-policy and indolence to escape the perils of warfare and live in ease and safety, addressed to them a reproachful and passionate remonstrance. Whether they had really meditated such a withdrawal from all share in the war of invasion, or the effect of their leader's expostulation was to drive them from their original purpose, they now, in answer to his impressive appeal, declared it to be their sincere intention to co-operate with their brethren; but, if so, they ought to have been more explicit at first.
num 32:16they came near--The narrative gives a picturesque description of this scene. The suppliants had shrunk back, dreading from the undisguised emotions of their leader that their request would be refused. But, perceiving, from the tenor of his discourse, that his objection was grounded only on the supposition that they would not cross the Jordan to assist their brethren, they became emboldened to approach him with assurances of their goodwill.
We will build sheepfolds here for our cattle, and cities for our little ones--that is, rebuild, repair. It would have been impossible within two months to found new cities, or even to reconstruct those which had been razed to the ground. Those cities of the Amorites were not absolutely demolished, and they probably consisted only of mud-built, or dry-stone walls.
num 32:17and our little ones shall dwell in the fenced cities because of the inhabitants of the land--There was good policy in leaving a sufficient force to protect the conquered region lest the enemy should attempt reprisals; and as only forty thousand of the Reubenites and the Gadites, and a half of Manasseh, passed over the Jordan (Jos 4:13), there were left for the security of the new possessions 70,580 men, besides women and children under twenty years (compare Num 26:7, Num 26:18, Num 26:34).
We ourselves will go ready armed--that is, all of us in a collective body, or as many as may be deemed necessary, while the rest of our number shall remain at home to provide for the sustenance and secure the protection of our families and flocks. (See on Jos 4:12).
num 32:20Moses said unto them, If ye will do this thing--with sincerity and zeal.
go before the Lord to war--The phrase was used in allusion to the order of march in which the tribes of Reuben and Gad immediately preceded the ark (see on Num. 2:10-31), or to the passage over the Jordan, in which the ark stood in mid-channel, while all the tribes marched by in succession (Jos 3:4), of course including those of Reuben and Gad, so that, literally, they passed over before the Lord and before the rest of Israel (Jos 4:13). Perhaps, however, the phrase is used merely in a general sense to denote their marching on an expedition, the purpose of which was blessed with the presence, and destined to promote the glory, of God. The displeasure which Moses had felt on the first mention of their proposal had disappeared on the strength of their solemn assurances. But a lurking suspicion of their motives seems still to have been lingering in his mind--he continued to speak to them in an admonitory strain; and he concluded by warning them that in case of their failing to redeem their pledge, the judgments of an offended God would assuredly fall upon them. This emphatic caution against such an eventuality throws a strong doubt on the honesty of their first intentions; and yet, whether through the opposing attitude or the strong invectives of Moses they had been brought to a better state of mind, their final reply showed that now all was right.
num 32:28concerning them Moses commanded--The arrangement itself, as well as the express terms on which he assented to it, was announced by the leader to the public authorities. The pastoral country the two tribes had desired was to be granted them on condition that they would lend their aid to their brethren in the approaching invasion of Canaan. If they refused or failed to perform their promise, those possessions should be forfeited, and they themselves compelled to go across the Jordan and fight for a settlement like the rest of their brethren.
num 32:33half the tribe of Manasseh--It is nowhere explained in the record how they were incorporated with the two tribes, or what broke this great tribe into two parts, of which one was left to follow the fortunes of its brethren in the settled life of the western hills, while the other was allowed to wander as a nomadic tribe over the pasture lands of Gilead and Bashan. They are not mentioned as accompanying Reuben and Gad in their application to Moses [Num 32:1]; neither were they included in his first directions (Num 32:25); but as they also were a people addicted to pastoral pursuits and possessed as immense flocks as the other two, Moses invited the half of them to remain, in consequence, probably, of finding that this region was more than sufficient for the pastoral wants of the others, and he may have given them the preference, as some have conjectured, for their valorous conduct in the contests with the Amorites (compare Num 32:39, with Jos 17:1).
num 32:34And the children of Gad built--(See on Num 32:16).
Dibon--identified with Dheban, now in ruins, an hour's distance from the Arnon (Mojeb).
Ataroth (Hebrew, "crowns")--There are several towns so called in Scripture, but this one in the tribe of Gad has not been identified.
Aroer--now Arair, standing on a precipice on the north bank of the Arnon.
num 32:35Atroth, Shophan, and Jaazer, &c.--Jaazer, near a famed fountain, Ain Hazier, the waters of which flow into Wady Schaib, about fifteen miles from Hesbon. Beth-nimrah, now Nimrin; Heshbon, now Hesban; Elealeh (Hebrew, "the high"), now Elaal; Kirjathaim (Hebrew, "the double city"); Nebo, now Neba, near the mountain of that name; Baal-meon, now Myoun, in ruins, where was a temple of Baal (Jos 13:17; Jer 48:23); Shibmah, or Shebam (Num 32:3), near Heshbon, famous for vines (Isa 16:9-10; Jer 48:32).
num 32:38(their names being changed)--either because it was the general custom of conquerors to do so; or, rather, because from the prohibition to mention the names of other gods (Exo 23:13), as Nebo and Baal were, it was expedient on the first settlement of the Israelites to obliterate all remembrance of those idols. (See Jos 13:17-20).
num 32:39Gilead--now Jelud.
num 32:41Havoth-jair--that is, "tent-villages." Jair, who captured them, was a descendant of Manasseh on his mother's side (Ch1 1:21-22).
num 32:42Nobah--also a distinguished person connected with the eastern branch of the tribe of Manasseh.