Judges 21:18
“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.”
Then the elders of the congregation said, How shall we do for wives for them that remain, seeing the women are destroyed out of Benjamin?
And they said, There must be an inheritance for them that be escaped of Benjamin, that a tribe be not destroyed out of Israel.
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.
Then they said, Behold, there is a feast of the Lord in Shiloh yearly in a place which is on the north side of Beth–el, on the east side of the highway that goeth up from Beth–el to Shechem, and on the south of Lebonah.
Therefore they commanded the children of Benjamin, saying, Go and lie in wait in the vineyards;
Counter-Arguments
The strongest case that this verse does not belong in this theme.

Cross-References
“Then began he to curse and to swear, saying, I know not the man. And immediately the cock crew.”
“Or if a soul swear, pronouncing with his lips to do evil, or to do good, whatsoever it be that a man shall pronounce with an oath, and it be hid from him; when he knoweth of it, then he shall be guilty in one of these.”
“Now the men of Israel had sworn in Mizpeh, saying, There shall not any of us give his daughter unto Benjamin to wife.”
“And the children of Israel said, Who is there among all the tribes of Israel that came not up with the congregation unto the Lord? For they had made a great oath concerning him that came not up to the Lord to Mizpeh, saying, He shall surely be put to death.”
“How shall we do for wives for them that remain, seeing we have sworn by the Lord that we will not give them of our daughters to wives?”