1 Kings 2:11

The days that David reigned over Israel [were] forty years; he reigned seven years in Hebron and thirty-three years in Jerusalem.

David [was] thirty years old when he began to reign; he reigned forty years.

And David the son of Jesse reigned over all Israel.

Treasury of Scripture Knowledge

And the days that David reigned over Israel were forty years: seven years reigned he in Hebron, and thirty and three years reigned he in Jerusalem.

David [was] thirty years old when he began to reign; he reigned forty years.

And David the son of Jesse reigned over all Israel.