Matthew Poole and continuators on Judges 21:18

18 Howbeit we may not give them wives of our daughters; for the children of Israel have sworn, saying, Cursed be he that giveth a wife to Benjamin .

i. e. To this Generation of Benjamites who have made themselves guilty of this foul Wickedness: but this Oath did not extend to their Posterity. And some think it had another exception, to wit, unless the surviving Benjamites could not otherwise be supplied with wives.