Numbers 32:23-27

But if you will not do so, behold, you have sinned against the LORD, and be sure your sin will find you out. Build yourselves cities for your little ones, and sheepfolds for your sheep, and do what you have promised.” The sons of Gad and the sons of Reuben spoke to Moses, saying, “Your servants will do just as my lord commands. Our little ones, our wives, our livestock and all our cattle shall remain there in the cities of Gilead; while your servants, everyone who is armed for war, will cross over in the presence of the LORD to battle, just as my lord says.”