Numbers 32:28

Israel's leaders were Eleazar, Joshua, and the heads of clans. They would help enforce the commands of Moses since he would soon die (compare Joshua 22:1–2).

concerning 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.

So concerning them Moses commanded. Moses annexes these conditions to his decision, lest, when the Reubenites and their companions had performed their military tasks:, they should be falsely alleged to have passed over Jordan for the purpose of seeking a new home; whilst at the same time, if they should deceive the other tribes, he provided that their cowardice and deceit should not profit them. In short, if they assisted their brethren in pursuance of their agreement, he commands that the territory, which he now grants them, should always remain theirs; but, if they departed from their promise, he would have them forced against their will to participate in the common allotment. For he does not assign them this portion in the midst of Canaan as a reward for their inertness, in case they should stay behind; but signifies that they should be forcibly and authoritatively carried onwards, so as to be subject to their brethren under all circumstances; since it, was not lawful for them to consult their own separate interests.

In laying down rules for the division of the land, as if it were soon to happen, he encourages the minds of all to confidence, so that they should more cheerfully hasten to pass over; as if the victory were not only already in their hands, but that the fruits of it were soon to be enjoyed.

So concerning them Moses commanded,.... That they should have a grant of the land they requested: this looks as if Moses determined the case himself, though perhaps it was by the vote, and with the consent of the whole court; only Moses strictly enjoined them to observe it, namely:

Eleazar the priest, and Joshua the son of Nun, and the chief fathers of the tribes of the children of Israel; and the rather he did this, because he knew that he should die, and not see either the thing itself or the conditions of it performed.

Moses thereupon commanded Eleazar, Joshua, and the heads of the tribes of Israel, i.e., the persons entrusted in Num 34:17. with the division of the land of Canaan, to give the Gadites and Reubenites the land of Gilead for a possession, after the conquest of Canaan, if they should go along with them across the Jordan equipped for battle. But if they should not do this, they were to be made possessors (i.e., to be settled; נאחז in a passive sense, whereas in Gen 34:10; Gen 47:27, it is reflective, to fix oneself firmly, to settle) in the land of Canaan along with the other tribes. In the latter case, therefore, they were not only to receive no possession in the land to the east of the Jordan, but were to be compelled to go over the Jordan with their wives and children, and to receive an inheritance there for the purpose of preventing a schism of the nation.