1 Samuel 29:8-9

8David said to Achish, “But what have I done? What have you found in your servant from the day when I [first] came before you to this day, that I may not go and fight against the enemies of my lord the king?”

9Achish answered David, “I know that you are blameless in my sight, like an angel of God; nevertheless the commanders of the Philistines have said, ‘He must not go up with us to the battle.’