Numbers 32:22

32:22 and the land is subdued before the Lord, then afterward you may return and be free of your obligation to the Lord and to Israel. This land will then be your possession in the Lord’s sight.

Numbers 32:29

32:29 Moses said to them: “If the Gadites and the Reubenites cross the Jordan with you, each one equipped for battle in the Lord’s presence, and you conquer the land, then you must allot them the territory of Gilead as their possession.