Numbers 32:28

“So concerning them Moses commanded, etc.] 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.”

“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.”

“32:28-30 Israel’s leaders—Eleazar, Joshua, and the heads of clans—would help enforce Moses’ terms (cp. Josh 22:1-2) since his death was imminent.”

“Jos 1:13 Numbers 32:29”

“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,…”