From Numbers 31-32
Q. How far would you go to protect your people from defilement and destruction?
Num 31.1-12 Story; The LORD commands Moses to send Israel’s armed men and destroy the Midianites
Num 31.13-20 Story; The warriors bring back the women and children. Because of Peor, Moses commands they kill all the women and children except the virgin girls. The warriors are to remain outside the camp and purify themselves.
Num 31.21-47 Story; Dividing up the plunder from the battle
Num 31.48-54 Story; None of the warriors were killed in the battle. They all presented contributions to the LORD.
Num 32.1-5 Story; The tribe of Reuben asks that the land before the Jordan be given them as their possession.
Num 32.6-15 Story; Moses recounts what happened when Israel initially refused to enter the promised land
Num 32.16-42 Story; The tribe of Reuben agree they will go into the promised land to fight with the rest of Israel.
Passage and Comments
This is probably one of the more difficult chapters to digest. Numbers 31, the aftermath of the battle with the Midianites.
[31:1] The LORD spoke to Moses, saying,  “Avenge the people of Israel on the Midianites. Afterward you shall be gathered to your people.”  So Moses spoke to the people, saying, “Arm men from among you for the war, that they may go against Midian to execute the LORD's vengeance on Midian. (Nu 31:1-3)
So they went to war against the Midianites. They kill all the males including Balaam son of Beor.
9 And the people of Israel took captive the women of Midian and their little ones, and they took as plunder all their cattle, their flocks, and all their goods. 10 All their cities in the places where they lived, and all their encampments, they burned with fire, 11 and took all the spoil and all the plunder, both of man and of beast. 12 Then they brought the captives and the plunder and the spoil to Moses, and to Eleazar the priest, and to the congregation of the people of Israel, at the camp on the plains of Moab by the Jordan at Jericho. 13 Moses and Eleazar the priest and all the chiefs of the congregation went to meet them outside the camp. 14 And Moses was angry with the officers of the army, the commanders of thousands and the commanders of hundreds, who had come from service in the war. 15 Moses said to them, “Have you let all the women live? (Num 31:9–15)
We might be excused to question Moses actions here, but we need to consider the wider context. Numbers 22 describes the elders of Midian approaching Balaam in order to get him to curse Israel. Presumably if he did, they would attack and wipe out Israel. Numbers 25 describes the incident at Peor where a Midianite woman coaxed a Israelite into defiling the sanctuary. The Midianites have had an ongoing agenda to either destroy or defile Israel. Moses recalls this saying;
 Behold, these, on Balaam's advice, caused the people of Israel to act treacherously against the LORD in the incident of Peor, and so the plague came among the congregation of the LORD. (Nu 31:16)
Twenty four thousand people died in the plague the LORD sent as a result of the Peor defilement. Moses is very anxious to avoid this again.
 Now therefore, kill every male among the little ones, and kill every woman who has known man by lying with him.  But all the young girls who have not known man by lying with him keep alive for yourselves.  Encamp outside the camp seven days. Whoever of you has killed any person and whoever has touched any slain, purify yourselves and your captives on the third day and on the seventh day. (Nu 31:17-19)
Moses is very protective over Israel and zealous for the holiness of the camp. He doesn’t want anymore to die as a result of the defilement foreigners can bring. To help understand Moses’ actions we need to consider the attempt of Midian to wipe out Israel, their defilement and the terrible consequences at Peor.
Story of Israel
Unfortunately there are not many in Israel's history who are as zealous to keep Israel undefiled.
Story of Jesus
This kind of zeal is perhaps still evident in the New Testament times. There were some in Israel who fought against the foreign powers who ruled them. Others were fiercely committed to the purity of Judaism. Jesus exhibits a kind of zeal as well, but his had a different twist, he said;
 And if your hand causes you to sin, cut it off. It is better for you to enter life crippled than with two hands to go to hell, to the unquenchable fire.  And if your foot causes you to sin, cut it off. It is better for you to enter life lame than with two feet to be thrown into hell.  And if your eye causes you to sin, tear it out. It is better for you to enter the kingdom of God with one eye than with two eyes to be thrown into hell,  ‘where their worm does not die and the fire is not quenched.’  For everyone will be salted with fire. (Mk 9:43-49)
Jesus is likewise very serious about sin and so should we be. Do what you can to cut it out of your life.