Samuel said to Saul, Yahweh sent me to anoint you to be king over his people, over Israel: now therefore listen you to the voice of the words of Yahweh.
Most scholars are sure Saul attacked the Amalekites who lived in the southern Judah Negev, though some feel he attacked an enclave of them in western Samaria. [Note: E.g., Diane Edelmann, "Saul’s Battle Against Amaleq (1 Samuel 15)," Journal for the Study of the Old Testament 35 (June 1986):74-81.] Saul did not destroy all the Amalekites at this time (1 Samuel 27:8; 1 Samuel 30:1; 2 Samuel 8:12). King Hezekiah completely annihilated them years later (1 Chronicles 4:43).