Numbers 32:31

Moses said to them, "If the children of Gad and the children of Reuben will pass with you over the Jordan, every man who is armed to battle, before Yahweh, and the land shall be subdued before you; then you shall give them the land of Gilead for a possession:

but if they will not pass over with you armed, they shall have possessions among you in the land of Canaan.

We will pass over armed before Yahweh into the land of Canaan, and the possession of our inheritance [shall remain] with us beyond the Jordan.

Moses gave to them, even to the children of Gad, and to the children of Reuben, and to the half-tribe of Manasseh the son of Joseph, the kingdom of Sihon king of the Amorites, and the kingdom of Og king of Bashan, the land, according to the cities of it with [their] borders, even the cities of the surrounding land.