Numbers 32:29-32
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.
32:30 But if they do not cross over with you armed, they must receive possessions among you in Canaan.”
32:31 Then the Gadites and the Reubenites answered, “Your servants will do what the Lord has spoken.
32:32 We will cross armed in the Lord’s presence into the land of Canaan, and then the possession of our inheritance that we inherit will be ours on this side of the Jordan River.”