1 Samuel 27:10-11

Achish would ask, “And whom did you raid today?” David would tell him, “Oh, the Negev of Judah,” or “The Negev of Jerahmeel,” or “The Negev of the Kenites.” He never left a single person alive lest one show up in Gath and report what David had really been doing. This is the way David operated all the time he lived in Philistine country.