1 Samuel 27:10-12

10When Achish asked, “Where did you raid today?” David replied, “Against the Negev (the South country) of Judah, and against the Negev of the Jerahmeelites, and against the Negev of the Kenites.”

11David did not leave a man or a woman alive to bring news to Gath, saying [to himself], “Otherwise they will tell about us, saying, ‘This is what David has done, and this has been his practice all the time that he has lived in the country of the Philistines.’ ”

12Achish believed David, saying, “He has certainly become hated by his people in Israel; so he will always be my servant.”