Numbers 31:16-18

Young's Literal Translation

¹⁶ lo, they -- they have been to the sons of Israel, through the word of Balaam, to cause a trespass against Jehovah in the matter of Peor, and the plague is in the company of Jehovah.

¹⁷ `And now, slay ye every male among the infants, yea, every woman known of man by the lying of a male ye have slain;

¹⁸ and all the infants among the women, who have not known the lying of a male, ye have kept alive for yourselves.