וְעַתָּ֕ה הִרְג֥וּ כָל־זָכָ֖ר בַּטָּ֑ף וְכָל־אִשָּׁ֗ה יֹדַ֥עַת אִ֛ישׁ לְמִשְׁכַּ֥ב זָכָ֖ר הֲרֹֽגוּ׃
Now therefore kill every male among the little ones, and kill every woman that hath known man by lying with him.
Read kabbalistic (mystical) interpretation of Numbers 31:17: and classical mystical sources.