Numbers 32:16-27

Then they came up to him and said, “We would like to build pens here for our livestock and cities for our women and children. But 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. We will not return to our homes until each of the Israelites has received their inheritance. We 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.” Then Moses said to them, “If you will do this—if you will arm yourselves before the LORD for battle and if all of you who are armed cross over the Jordan before the LORD until he has driven his enemies out before him— then 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. “But if you fail to do this, you will be sinning against the LORD; and you may be sure that your sin will find you out. Build cities for your women and children, and pens for your flocks, but do what you have promised.” The Gadites and Reubenites said to Moses, “We your servants will do as our lord commands. Our children and wives, our flocks and herds will remain here in the cities of Gilead. But your servants, every man who is armed for battle, will cross over to fight before the LORD, just as our lord says.”