Numbers 32:20-22

20Moses said to the men, ‘You must really do as you have said. You must take your weapons and go to fight for the Lord.

21Your men must cross over the Jordan River with the other tribes. You must continue to fight until we have won against all our enemies.

22When the Lord has power over the whole land, then you can return here. You will have done everything that the Lord wants you to do. You will have helped the whole Israelite nation in the way that you should. The Lord will give to you this land on the east side of the Jordan River.