Judges 21:4

²  And the people came to the house of God, and abode there till even before God, and lifted up their voices, and wept sore;

³  And said, O LORD God of Israel, why is this come to pass in Israel, that there should be to day one tribe lacking in Israel?

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

⁵  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.

⁶  And the children of Israel repented them for Benjamin their brother, and said, There is one tribe cut off from Israel this day.