Numbers 32:17-22

17But we will arm ourselves for battle and go ahead of the Israelites until we have brought them to their place. Meanwhile our women and children will live in fortified cities, for protection from the inhabitants of the land. 18We will not return to our homes until each of the Israelites has received their inheritance. 19We will not receive any inheritance with them on the other side of the Jordan, because our inheritance has come to us on the east side of the Jordan.” 20Then Moses said to them, “If you will do this—if you will arm yourselves before the Lord for battle 21and if all of you who are armed cross over the Jordan before the Lord until he has driven his enemies out before him— 22then when the land is subdued before the Lord, you may return and be free from your obligation to the Lord and to Israel. And this land will be your possession before the Lord.