Saul rules for 40 years (Acts 13:21), then David for 40 years (2Samuel 5:4). The length of the reign, which had to appear in 1Samuel 13:1, can be deduced from the biography of Ishbosheth, a son of Saul, who was born at the beginning of his father's reign (1Chronique 8:33), because he was 40 years at Saul's death (2Samuel 2:10). Josephus hesitated between 20 and 40 years (Jewish Antiquities VI:378, X:143) and also in the sum of reigns (Jewish Antiquities VIII:61, XX:230).