Numbers 32:23-33
English Standard Version
Chapter 32
23But if you will not do so, behold, you have sinned against the Lord, and be sure your sin will find you out. 24Build cities for your little ones and folds for your sheep, and do what you have promised." 25And the people of Gad and the people of Reuben said to Moses, "Your servants will do as my lord commands. 26Our little ones, our wives, our livestock, and all our cattle shall remain there in the cities of Gilead, 27but your servants will pass over, every man who is armed for war, before the Lord to battle, as my lord orders."
28So Moses gave command concerning them to Eleazar the priest and to Joshua the son of Nun and to the heads of the fathers ' houses of the tribes of the people of Israel.
29And Moses said to them, "If the people of Gad and the people of Reuben, every man who is armed to battle before the Lord, will pass with you over the Jordan and the land shall be subdued before you, then you shall give them the land of Gilead for a possession.
30However, if they will not pass over with you armed, they shall have possessions among you in the land of Canaan."
31And the people of Gad and the people of Reuben answered, "What the Lord has said to your servants, we will 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."