Midian was a son of Abraham by Keturah (Genesis 25:1-6). When Moses fled from Egypt forty years before the Exodus (Exodus 2:15-21), he helped the daughters of Jethro, the Priest of Midian, and married one of his daughters (Zipporah). Therefore, the Midianites were descendants of Moses, as well as the Levites. Through the influence of Balaam the Midianite women and girls were able to seduce the men of Israel. Because of this, God commanded Moses to destroy the nation of Midian (Numbers 25:16-18). In Numbers 31 Moses now receives the order to execute this command.
The spiritual laws that God has given are just as absolute as natural laws. Galatians 6:7 tells us, "Be not deceived; God is not mocked; for whatsoever a man soweth, that shall he also reap." Also, Numbers 32:33 tells us, "Be sure your sin will find you out." If a man sows wheat, he reaps wheat; if he sows corn, he reaps corn. Spiritual laws are just as certain. In the righteous government of God, sin always brings sorrow and suffering.
In chapter 32 we see the request and dispute of Reuben, Gad, and Manasseh with Moses, concerning the portioning of the land. The request was a selfish one, characterized by worldly convenience. The property they chose was outside the Promised Land and they, thereby, showed unbelief and a willingness to shun war. Moses' rebuke in verses 6-15 warned them of the fruits of unbelief at Kadesh-Barnea when the spies were sent out. Their compromise to join their brothers was accepted, and can be compared to Lot's selfish decision (Genesis 13:5-11). In the final arrangement (verses 25-42), the tribes of Reuben and Gad and the half tribe of Manasseh obtained the rich grazing lands of Transjordan. We will see later, in II Kings 15:29 and I Chronicles 5:25,26, that their choice resulted in unbelief and world conformity.
Chapter 33 gives the summary of the journey from Egypt. The first and second stages are given in verses 1-17; the third and fourth stages in verses 18-49; and the directions to exterminate the Canaanites are given in verses 50-56. Notice particularly verses 55 and 56. God explains here the results of disobedience concerning His instructions to exterminate the Canaanites. Again we are reminded that God demands complete obedience to His Word; partial obedience will bring judgment and chastisement to offenders.