Numbers 31:16

12They brought the captives with the prey and the plunder, to Moses, and to Eleazar the priest, and to the congregation of the children of Israel, to the camp at the plains of Moab, which are by the Jordan at Jericho.

13Moses and Eleazar the priest, with all the princes of the congregation, went out to meet them outside of the camp.

14Moses was angry with the officers of the army, the captains of thousands and the captains of hundreds, who came from the service of the war.

15Moses said to them, “Have you saved all the women alive?

16Behold, these caused the children of Israel, through the counsel of Balaam, to commit trespass against the LORD in the matter of Peor, and so the plague was among the congregation of the LORD.

17Now therefore kill every male among the little ones, and kill every woman who has known man by lying with him.

18But all the girls, who have not known man by lying with him, keep alive for yourselves.

19“Encamp outside of the camp for seven days. Whoever has killed any person, and whoever has touched any slain, purify yourselves on the third day and on the seventh day, you and your captives.

20You shall purify every garment, and all that is made of skin, and all work of goats’ hair, and all things made of wood.”