Numbers 32:20-29

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.

32:23 “But if you do not do this, then look, you will have sinned against the Lord. And know that your sin will find you out. 32:24 So build cities for your descendants and pens for your sheep, but do what you have said you would do.”

32:25 So the Gadites and the Reubenites replied to Moses, “Your servants will do as my lord commands. 32:26 Our children, our wives, our flocks, and all our livestock will be there in the cities of Gilead, 32:27 but your servants will cross over, every man armed for war, to do battle in the Lord’s presence, just as my lord says.”

32:28 So Moses gave orders about them to Eleazar the priest, to Joshua son of Nun, and to the heads of the families of the Israelite tribes. 32:29 Moses said to them: “If the Gadites and the Reubenites cross the Jordan with you, each one equipped for battle in the Lord’s presence, and you conquer the land, then you must allot them the territory of Gilead as their possession.

Deuteronomy 3:16-20

3:16 To the Reubenites and Gadites I allocated the territory extending from Gilead as far as Wadi Arnon (the exact middle of the wadi was a boundary) all the way to the Wadi Jabbok, the Ammonite border. 3:17 The Arabah and the Jordan River were also a border, from the sea of Chinnereth to the sea of the Arabah (that is, the Salt Sea), beneath the watershed of Pisgah to the east.

Instructions to the Transjordanian Tribes

3:18 At that time I instructed you as follows: “The Lord your God has given you this land for your possession. You warriors are to cross over before your fellow Israelites equipped for battle. 3:19 But your wives, children, and livestock (of which I know you have many) may remain in the cities I have given you. 3:20 You must fight until the Lord gives your countrymen victory as he did you and they take possession of the land that the Lord your God is giving them on the other side of the Jordan River. Then each of you may return to his own territory that I have given you.”