Numbers 32:23–30

23But if ye will not do so, behold, ye have sinned against Jehovah; and be sure your sin will find you out. 24Build you cities for your little ones, and folds for your sheep; and do that which hath proceeded out of your mouth. 25And the children of Gad and the children of Reuben spake unto Moses, saying, Thy servants will do as my lord commandeth. 26Our little ones, our wives, our flocks, and all our cattle, shall be there in the cities of Gilead; 27but thy servants will pass over, every man that is armed for war, before Jehovah to battle, as my lord saith.

28So Moses gave charge 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 children of Israel. 29And Moses said unto them, If the children of Gad and the children of Reuben will pass with you over the Jordan, every man that is armed to battle, before Jehovah, and the land shall be subdued before you; then ye 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.