Numbers 31:14-18

And Moses was wroth with the officers of the host, the captains of thousands and the captains of hundreds, who came from the service of the war. And Moses said unto them, Have ye saved all the women alive? Behold, these caused the children of Israel, through the counsel of Balaam, to commit trespass against Jehovah in the matter of Peor, and so the plague was among the congregation of Jehovah. Now therefore kill every male among the little ones, and kill every woman that hath known man by lying with him. But all the women-children, that have not known man by lying with him, keep alive for yourselves.