Numbers 31:17

Now therefore kill every male among the little ones,.... Which they had taken and brought captives, Numbers 31:9

and kill every woman that hath known man by lying with him; who might be such, at least many of them, who had lain with Israelitish men; and as the adulterers had been put to death, so now the adulteresses; or they were ordered to, be slain, even all of them, lest they should entice the children of Israel to uncleanness, and so to idolatry again: now these were known to be such, either by conjecture at their age, or rather, through the examination of matrons, unless it can be thought, as it is by some, that it was by divine revelation.