Numbers 32:31

29Moses 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 the LORD, and the land is subdued before you, then you shall give them the land of Gilead for a possession;

30but if they will not pass over with you armed, they shall have possessions among you in the land of Canaan.”

31The children of Gad and the children of Reuben answered, saying, “As the LORD has said to your servants, so will we do.

32We will pass over armed before the LORD into the land of Canaan, and the possession of our inheritance shall remain with us beyond the Jordan.”

33Moses 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 its cities and borders, even the cities of the surrounding land.