Numbers 32:31-33

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

32We will cross over armed before the Lord into the land of Canaan, so that the possession of our inheritance on [the east] side of the Jordan may be ours.”

33So Moses gave to them, to the sons of Gad and to the sons of Reuben and to the half-tribe of Manasseh the son of Joseph, the kingdom of Sihon, the king of the Amorites and the kingdom of Og, the king of Bashan, the land with its cities and territories, the cities of the surrounding land.