Numbers 32:16-19 New International Version (NIV)
16 Then they came up to him and said, “We would like to build pens here for our livestock and cities for our women and children. 17 But we will arm ourselves for battle and go ahead of the Israelites until we have brought them to their place. Meanwhile our women and children will live in fortified cities, for protection from the inhabitants of the land. 18 We will not return to our homes until each of the Israelites has received their inheritance. 19 We will not receive any inheritance with them on the other side of the Jordan, because our inheritance has come to us on the east side of the Jordan.”
The land on the east side of the Jordan had been conquered. The tribes of Reuban, Gad and half of Manasseh promised to keep working with the others until everyone’s land was conquered. When you have others help you, do not make excuses to not help them. Work to finish the whole job even if the part you are helping with does not directly benefit you.