Verses 20 through 42 speak of the permission of Moses.
Moses was moved by the word of Reuben and Gad and agreed with their promise (vv. 20-22). This proves that Moses was not a dictator but that he was willing to accept others' reasonable proposals and opinions.
Moses' permission was given with the condition that every armed man of theirs would pass over the Jordan before Jehovah, until He had driven His enemies from before Him and the land was subdued before Him. Then, after that, they would return and be free of obligation to Jehovah and to Israel (vv. 21-22). Reuben and Gad had said, "until we have brought them to their place," but Moses said, "until He [Jehovah] has driven out His enemies from before Him and the land is subdued before Jehovah." This would be due to Him, not to Reuben and Gad.
In verse 22 Moses uses the word obligation. Whenever we have our own choice, we will owe something for our choice and will be under some kind of obligation. In serving the Lord, we need to learn never to be obligated in this way. We need to learn not to have our own choice and thereby not to be obligated to God and to His people.
In verse 24 we see that Moses allowed them to build cities for their little ones and folds for their sheep.
Moses gave command to Eleazar the priest, to Joshua the son of Nun, and to the heads of the fathers' houses of the sons of Israel concerning the two tribes, regarding their keeping their promise to Moses (vv. 28-32). These two tribes were obligated to remember their promise and to fulfill it.
According to verses 33 through 42, Moses gave to the two tribes and to the half-tribe of Manasseh the son of Joseph the kingdom of Sihon king of the Amorites and the kingdom of Og king of Bashan, the land and its cities with their territories.
It may seem that in this chapter a good settlement was made concerning the request of the two tribes, Reuben and Gad. Actually, this situation was not pleasant, for these tribes were standing for themselves.
This may also be our situation in our married life and church life. Often in making a choice a brother will care not for his wife but for himself. He may say that he is for his wife, but deep in his heart he is for himself. Likewise, as the elders from various churches are having fellowship, the elders of each church may stand for themselves and their interests, not for the other churches, with each elder claiming that his concern is for the Lord's purpose and the building up of the Body. These illustrations show us that it is difficult for us not to have our own choice. It is a terrible thing to have our self-choice. Instead of having our own choice, we should leave the matter to the Lord.
If in the Lord's recovery our standing is that we will not have our own choice but leave the choice to the Lord, there will not be any problems among us. However, if we have our own choice, there will eventually be problems and suffering. Let us learn not to follow Reuben and Gad, but to follow the other tribes who allowed the Lord to make the choice for them. Let us wait for the lot and not have our own choice.