'Tribe' in the Bible

Saul answered: "Am I not a descendant of Benjamin from the least of the tribes of Israel? Isn't my family the least important of all the families of the tribe of Benjamin? Why have you spoken to me like this?"

Samuel brought forward all the tribes of Israel, and the tribe of Benjamin was chosen.

Then he brought forward the tribe of Benjamin according to its families, and the family of Matri was chosen. Finally, Kish's son Saul was chosen, but when they looked for him, they couldn't find him.