1 Samuel 29:3-4; 1 Samuel 29:9
The 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."
But the Philistine commanders were angry with him and said, "Send the man back, that he may return to the place you assigned him. He must not go with us into battle, or he will turn against us during the fighting. How better could he regain his master's favor than by taking the heads of our own men?
Achish answered, "I know that you have been as pleasing in my eyes as an angel of God; nevertheless, the Philistine commanders have said, 'He must not go up with us into battle.'