Joshua 22:2

And Moses said unto them, If ye will do this thing, if ye will go armed before the LORD to war, And will go all of you armed over Jordan before the LORD, until he hath driven out his enemies from before him, And the land be subdued before the LORD: then afterward ye shall return, and be guiltless before the LORD, and before Israel; and this land shall be your possession before the LORD. But if ye will not do so, behold, ye have sinned against the LORD: and be sure your sin will find you out. Build you cities for your little ones, and folds for your sheep; and do that which hath proceeded out of your mouth. And the children of Gad and the children of Reuben spake unto Moses, saying, Thy servants will do as my lord commandeth. Our little ones, our wives, our flocks, and all our cattle, shall be there in the cities of Gilead: But thy servants will pass over, every man armed for war, before the Lord to battle, as my lord saith. So concerning them Moses commanded Eleazar the priest, and Joshua the son of Nun, and the chief fathers of the tribes of the children of Israel: And Moses said unto them, If the children of Gad and the children of Reuben will pass with you over Jordan, every man armed to battle, before the LORD, and the land shall be subdued before you; then ye shall give them the land of Gilead for a possession:

And unto the Reubenites and unto the Gadites I gave from Gilead even unto the river Arnon half the valley, and the border even unto the river Jabbok, which is the border of the children of Ammon; The plain also, and Jordan, and the coast thereof, from Chinnereth even unto the sea of the plain, even the salt sea, under Ashdothpisgah eastward. And I commanded you at that time, saying, The LORD your God hath given you this land to possess it: ye shall pass over armed before your brethren the children of Israel, all that are meet for the war. But your wives, and your little ones, and your cattle, (for I know that ye have much cattle,) shall abide in your cities which I have given you; Until the LORD have given rest unto your brethren, as well as unto you, and until they also possess the land which the LORD your God hath given them beyond Jordan: and then shall ye return every man unto his possession, which I have given you.