1 Samuel 29:3-5

3Then the Philistine commanders said, “What are these Hebrews doing here?” Achish said to the Philistine commanders, “No! That’s David, servant of Israel’s King Saul—he’s been with me today for over a year, and I’ve not found any fault in him since the day he defected to me until now.”

4But the Philistine commanders got angry with him, and the Philistine commanders said to him, “Make this man go back—back to his place you assigned him. He must not go down with us to the battle, or in the battle he might become our adversary. For how would this fellow appease his lord? Wouldn’t it be with the heads of our men?

5Isn’t this one David, about whom they were singing in dances saying: ‘Saul has slain his thousands, and David his ten thousands?’”