Judges 21:4-6

4And it came to pass on the morrow, that the people rose early, and built there an altar, and offered up burnt-offerings and peace-offerings.

5And the children of Israel said, Who is there among all the tribes of Israel that came not up with the congregation to Jehovah? For they had [made] a great oath concerning him that came not up to Jehovah to Mizpah, saying, He shall certainly be put to death.

6And the children of Israel repented them for Benjamin their brother, and said, To-day is one tribe extirpated from Israel.