1 Samuel 10:21
When he had caused the tribe of Benjamin to come near by their families, the family of Matri was taken, and Saul the son of Kish was taken: and when they sought him, he could not be found. When he had caused the tribe of Benjamin to come near by their families, the family of Matri was taken, and Saul the son of Kish was taken: and when they sought him, he could not be found.
The verse records the public choosing of Saul as king by lot at Mizpeh in answer to Israel's demand for a king, when the tribe of Benjamin was taken, then the family of Matri, then Saul the son of Kish. When the people looked for him he was absent from the assembly and could not be found, so he had to be brought back and set before them. His hiding reflected his sense of the grave responsibility he was about to bear. Although this was God's choice, the selection of a king from Benjamin, the smallest tribe, was rejected by some Israelites who resented that the king did not come from Judah or Ephraim.