1 Samuel 27:9-11

9David attacked the land and did not leave a man or a woman alive, but he took the sheep, the cattle, the donkeys, the camels, and the clothing, and returned to Achish.

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.’ ”