Matthew Poole and continuators on Judges 21:11

11 And this is the thing that ye shall do, Ye shall utterly destroy every male, and every woman that hath lien by man .

But not the Virgins, as appears from the next Verses. It is questionable, whether they were not obliged to destroy these also by vertue of their Oath, and of Gods express Command concerning Devoted Persons, such as these certainly were, that they should surely be put to death, Levit. 27. 29. which was also particularly enjoyned and practised in such Cases, as Deut. 13. Ios. 7. &c. But the natural and necessary duty of preserving a Tribe from total Ruine, might seem to render the case difficult and doubtful, and incline their Opinions, as well as their Affections, to the more favourable side. And it may be, the Lord, whom they were here consulting with upon all their occasions, gave them a Dispensation thus to do, though that be not expressed; which is the case of many other things which were done, though not Recorded; as this very Oath was omitted in its proper place, and had not been Recorded if this extraordinary occasion had not been offered.

Marginal references: Numb. 31▪; Heb. knoweth the lying with man.