It is generally assumed that Saul was around thirty years of age when he began to rule as king over Israel (see 1 Samuel 13:1), and that he reigned for a period of at least forty years (see Acts 13:21). His official rule as king began after his revelation to the people of Israel (1 Samuel 10:17–27), though it was only after the defeat of the Ammonites (1 Samuel 11:1–15) and Samuel’s farewell speech (1 Samuel 12:1–25) that his authority was firmly established.
47 When Saul had taken the kingship over Israel, he fought against all his enemies on every side, against Moab, against the Ammonites, against Edom, against the kings of Zobah, and against the Philistines. Wherever he turned he routed them.