Numbers 32:13-23 GNT

13 The Lord became angry with the people and made them wander in the wilderness forty years until that whole generation that had displeased him was dead.
14 And now you have taken your ancestors' place, a new generation of sinful people ready to bring down the fierce anger of the Lord on Israel again.
15 If you people of Reuben and Gad refuse to follow him now, he will once again abandon all these people in the wilderness, and you will be responsible for their destruction."
16 They approached Moses and said, "First, allow us to build stone enclosures here for our sheep and fortified towns for our dependents.
17 Then we will be ready to go with the other Israelites into battle and lead the attack until we have settled them in the land that will be theirs. In the meantime, our dependents can live here in the fortified towns, safe from the people of this land.
18 We will not return to our homes until all the other Israelites have taken possession of the land assigned to them.
19 We will not take possession of any property among them on the other side of the Jordan, because we have received our share here east of the Jordan."
20 Moses answered, "If you really mean what you say, then here in the presence of the Lord get ready to go into battle.
21 All your fighting men are to cross the Jordan and under the command of the Lord they are to attack our enemies until the Lord defeats them
22 and takes possession of the land. After that, you may return, because you will have fulfilled your obligation to the Lord and to the other Israelites. Then the Lord will acknowledge that this land east of the Jordan is yours.
23 But if you do not keep your promise, I warn you that you will be sinning against the Lord. Make no mistake about it; you will be punished for your sin.