Acts 13:21
And afterward they desired a king: and God gave unto them Saul the son of Cis, a man of the tribe of Benjamin, by the space of forty years. And afterward they desired a king: and God gave unto them Saul the son of Cis, a man of the tribe of Benjamin, by the space of forty years.
Afterward they desired a king, and God gave them Saul the son of Cis, a man of the tribe of Benjamin, for the space of forty years. This statement belongs to Paul's account of how God dealt with Israel. That account begins with Israel's deliverance from Egypt.
Paul rehearsed this history to point to God's promise of a Saviour from David's line. He identified Jesus as that promised Saviour, the Messiah foretold in prophecy.