Matthew Henry Commentary Numbers 31:7-12

"And they warred against Midian, as Jehovah commanded Moses; and they slew every male. And they slew the kings of Midian with the rest of their slain: Evi, and Rekem, and Zur, and Hur, and Reba, the five kings of Midian: Balaam also the son of Beor they slew with the sword. And the children of Israel took captive the women of Midian and their little ones; and all their cattle, and all their flocks, and all their goods, they took for a prey. And all their cities in the places wherein they dwelt, and all their encampments, they burnt with fire. And they took all the spoil, and all the prey, both of man and of beast. And they brought the captives, and the prey, and the spoil, unto Moses, and unto Eleazar the priest, and unto the congregation of the children of Israel, unto the camp at the plains of Moab, which are by the Jordan at Jericho." — Numbers 31:7-12 (ASV)

The Israelites killed the Kings of Midian. They killed Balaam. God's overruling providence brought him there, and their just vengeance found him. If he himself had rightly believed what he had said about the happy state of Israel, he would not have thus consorted with the enemies of Israel. The Midianites' wicked schemes were Balaam's designs: it was just that he should perish with them (Hosea 4:5).

They took the women and children captive. They burned their cities and castles, and returned to the camp.