1 Samuel 29:1-3

Now the Philistines gathered together all their armies to Aphek, while the Israelites were camping by the spring which is in Jezreel. And the lords of the Philistines were proceeding on by hundreds and by thousands, and David and his men were proceeding on in the rear with Achish. Then the commanders of the Philistines said, “What are these Hebrews doing here?” And Achish said to the commanders of the Philistines, “Is this not David, the servant of Saul the king of Israel, who has been with me these days, or rather these years, and I have found no fault in him from the day he deserted to me to this day?”