The two tribes made their request because of what they had (a very great multitude of cattle—v. 1) and because of what they saw (a land good for livestock—v. 4). This was the reason for their choice.
Self-choice, even in the church life, comes from two things—considering what we have and need and considering how a particular situation or opportunity that we see in front of us fits in with our needs. This should not be our situation in the church life or in the service of the Lord. Both in the church life and in the Lord's work, we need to resist the temptation to have our self-choice for the purpose of taking care of our own welfare.
We need to learn the lesson of not considering what we have or what is in front of us but leaving our future in the hand of the Lord. We should not try to have our own choice in the church life or in the Lord's service. If you insist on having your own choice, be prepared to suffer as a result. Our choice is not the best selection. We are shortsighted and somewhat selfish, so it is difficult for us to be pure in motive, desire, intention, goal, and purpose. We should be willing to give up our choice and tell the Lord that we do not have any choice of our own.
The land requested by Reuben and Gad could be reached without crossing the river Jordan. Without crossing the Jordan signifies without having the old man dealt with and buried. Only after we have had the old man dealt with and buried are we in a position to talk about possessing the good land for our enjoyment.
Reuben and Gad did not receive the promise of the good land with the body of the children of Israel. This signifies receiving the enjoyment of Christ separately, without the Body of Christ.
In verses 6 through 15 we have the rebuking and warning of Moses.
"Moses said to the sons of Gad and to the sons of Reuben, Shall your brothers go to the war while you stay here?" (v. 6). Here Moses was rebuking them for their selfishness. Moses seemed to be saying, "You are considering the welfare of your tribes. What about the other tribes? If the other tribes follow your pattern, every tribe will have its own choice, and we will not have a way to distribute the land."
In verses 7 through 15 Moses warned Reuben and Gad with the pitiful story of Kadesh-barnea, a story of unbelief. In verse 7 he said to them, "Why will you discourage the heart of the sons of Israel from going over into the land which Jehovah has given them?" Moses might have thought that they were afraid of the giants in the land and that this fear would have discouraged all the other tribes.