1 Samuel 29:2-3

2As the Philistine rulers marched with their units of hundreds and thousands, David and his men were marching at the rear with Achish.

3The commanders of the Philistines asked, “What about these Hebrews?” Achish replied, “Is this not David, who was an officer of Saul king of Israel? He has already been with me for over a year, and from the day he left Saul until now, I have found no fault in him.”