Numbers 32:17-22

32:17 but we will maintain ourselves in armed readiness and go before the Israelites until whenever we have brought them to their place. Our descendants will be living in fortified towns as a protection against the inhabitants of the land. 32:18 We will not return to our homes until every Israelite has his inheritance. 32:19 For we will not accept any inheritance on the other side of the Jordan River and beyond, because our inheritance has come to us on this eastern side of the Jordan.”

32:20 Then Moses replied, “If you will do this thing, and if you will arm yourselves for battle before the Lord, 32:21 and if all your armed men cross the Jordan before the Lord until he drives out his enemies from his presence 32:22 and the land is subdued before the Lord, then afterward you may return and be free of your obligation to the Lord and to Israel. This land will then be your possession in the Lord’s sight.