Massacre of the Midianites
Here's part of it:
Rabbi Brant Rosen, in a post on Radical Torah, points out that this attack "can only be described as holy war." I found his reflections on this text, and what we should make of it today, to be quite illuminating. I would encourage you to read it, if you haven't already.
They did battle against Midian, as the Lord had commanded Moses, and killed every male. They killed the kings of Midian: Evi, Rekem, Zur, Hur, and Reba, the five kings of Midian, in addition to others who were slain by them; and they also killed Balaam son of Beor with the sword.
The Israelites took the women of Midian and their little ones captive; and they took all their cattle, their flocks, and all their goods as booty. All their towns where they had settled, and all their encampments, they burned, but they took all the spoil and all the booty, both people and animals. Then they brought the captives and the booty and the spoil to Moses, to Eleazar the priest, and to the congregation of the Israelites, at the camp on the plains of Moab by the Jordan at Jericho.
Moses, Eleazar the priest, and all the leaders of the congregation went to meet them outside the camp. Moses became angry with the officers of the army, the commanders of thousands and the commanders of hundreds, who had come from service in the war. Moses said to them, "Have you allowed all the women to live? These women here, on Balaam's advice, made the Israelites act treacherously against the Lord in the affair of Peor, so that the plague came among the congregation of the Lord. Now therefore, kill every male among the little ones, and kill every woman who has known a man by sleeping with him. But all the young girls who have not known a man by sleeping with him, keep alive for yourselves." (Numbers 31.7-18)