Numbers 31:15-18 Revised Standard Version (RSV)
15 Moses said to them, “Have you let all the women live? 16 Behold, these caused the people of Israel, by the counsel of Balaam, to act treacherously against the Lord in the matter of Pe′or, and so the plague came among the congregation of the Lord. 17 Now therefore, kill every male among the little ones, and kill every woman who has known man by lying with him. 18 But all the young girls who have not known man by lying with him, keep alive for yourselves.