Matthew Poole and continuators on Judges 21:1

NOw the men of Israel had sworn in Mizpeh, saying, There shall not any of us give his daughter unto Benjamin to wise .

In the beginning of this War, after the whole Tribe had espoused the quarrel of the Men of Gibeah, Iudg. 20. 13, 14

They do not (as some suppose) here swear the utter extirpation of the Tribe, which fell out beyond their expectation, Iudg. 21. 3, 6. but only not to give their Daughters to those Men who should survive; justly esteeming them for their harbarous Villany, to be as bad as the worst of Heathens with whom they were forbidden to Marry. In this Case the Benjamites might have Married among themselves, if any of their Men and Women were left alive.