Numbers 32:20-27

20Moses replied, “If you will do this—if you will arm yourselves before the LORD for battle, 21and if every one of your armed men crosses 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 of obligation to the LORD and to Israel. And this land will belong to you as a possession before the LORD. 23But if you do not do this, you will certainly sin against the LORD—and be assured that your sin will find you out. 24Build cities for your little ones and folds for your flocks, but do what you have promised.”

25The Gadites and Reubenites said to Moses, “Your servants will do just as our lord commands. 26Our children, our wives, our livestock, and all our animals will remain here in the cities of Gilead. 27But your servants are equipped for war, and every man will cross over to the battle before the LORD, just as our lord says.”