Deuteronomy 3:18

"And I commanded you at that time, saying, Jehovah your God hath given you this land to possess it: ye shall pass over armed before your brethren the children of Israel, all the men of valor. But your wives, and your little ones, and your cattle (I know that ye have much cattle), shall abide in your cities which I have given you, until Jehovah give rest unto your brethren, as unto you, and they also possess the land which Jehovah your God giveth them beyond the Jordan: then shall ye return every man unto his possession, which I have given you. And I commanded Joshua at that time, saying, Thine eyes have seen all that Jehovah your God hath done unto these two kings: so shall Jehovah do unto all the kingdoms whither thou goest over. Ye shall not fear them; for Jehovah your God, he it is that fighteth for you."

This passage is concerned principally with admonitions to the tribes to be settled east of Jordan, reminding them of their sworn promise to give their full military support to the remaining portion of Israel in their projected conquest of Canaan. The record of this obligation assumed by the eastern tribes is found in Numbers 32:28-32. It is our conviction that the action of those eastern tribes was sinful. They made promises that it would be impossible for them to keep, and the reason why Moses finally acceded to their request probably lies in the fact that the whole of the twelve tribes probably supported the suggestion whole-heartedly. Why? By settling the two and one-half tribes east of Jordan, there would have been considerably more land for the remaining tribes west of Jordan! At any rate, that is the way they did it.

Did those eastern tribes keep those glorying promises? Certainly not! All of their wives and their children and their cattle, and all their property - what about all that? Would it have been possible for all that to have been left unprotected? Anyone can see that it would have been impossible for the eastern two and one half tribes to have left such treasures unprotected. So what did they do? The number of fighting men accredited to those eastern two and one-half tribes was 110,580 fighting men. How many supported Joshua? Only 40,000 men actually crossed Jordan to aid the conquest (Joshua 4:13). That means that 70,580 men had no part in aiding Joshua and the other nine and one-half tribes.[17] Right here we have the key to Israel's failure to drive out "all the inhabitants" of Canaan. The simple truth is, they did not have sufficient forces to do it, and that remnant of the pagan world that remained in Canaan eventually seduced the whole nation of Israel and led to their destruction and captivity. The whole dark tragedy began right here with the GREED of those eastern tribes. It is always thus when men have a big eye on what is their immediate benefit rather than upon what is the will of God.

"The subsequent history of the trans-Jordanic tribes is a melancholy commentary upon the foolishness of the choice made by those eastern tribes."[18] In the later history of Israel, those two tribes of Reuben and Gad "were the very first to go into captivity because they transgressed against the commandment of the God of their fathers and went a-whoring after strange gods."[19]

God, of course, would deliver Canaan to Israel, but God did not choose to do it without the full cooperation of all Israel. G. Ernest Wright accurately discerned the connection between God's election and the human means by which His sovereignty is executed:

"It seems contradictory, but it is typical of the Biblical way of thinking. God's sovereignty and His election are joined together, but God works through chosen instruments whose calling carries with it great responsibility."[20]

The understanding of this reveals the tragedy of those two and one-half tribes' defection from the armies of Israel. When God's people do not cooperate by full obedience to His will, the intended blessings are short-circuited and denied, not because of God's unwillingness to bless, but because of man's unwillingness to obey.