I Samuel 29:1-3

Then the Philistines gathered together all their armies at Aphek, and the Israelites encamped by a fountain which is in Jezreel. And the lords of the Philistines passed in review by hundreds and by thousands, but David and his men passed in review at the rear with Achish. Then the princes of the Philistines said, “What are these Hebrews doing here?” And Achish said to the princes of the Philistines, “Is this not David, the servant of Saul king of Israel, who has been with me these days, or these years? And to this day I have found no fault in him since he defected to me.”