Judges 21:4 WEB

²  The people came to Bethel, and sat there until evening before God, and lifted up their voices, and wept sore.

³  They said, Yahweh, the God of Israel, why has this happened in Israel, that there should be today one tribe lacking in Israel?

⁴  It happened on the next day that the people rose early, and built there an altar, and offered burnt offerings and peace-offerings.

⁵  The children of Israel said, Who is there among all the tribes of Israel who didn't come up in the assembly to Yahweh? For they had made a great oath concerning him who didn't come up to Yahweh to Mizpah, saying, He shall surely be put to death.

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