Numbers 31:15-18

15“Have you let every female live?” he asked them.

16“Yet they are the ones who, at Balaam’s advice, incited the Israelites to unfaithfulness against the Lord in the Peor incident, so that the plague came against the Lord’s community.

17So now, kill every male among the dependents and kill every woman who has gone to bed with a man,

18but keep alive for yourselves all the young females who have not gone to bed with a man.