1 Samuel 29:1-4

Now the Philistines gathered together all their armies to Aphek, while the Israelites were camping by the spring which is in Jezreel.

And the governors of the Philistines were proceeding on, leading hundreds and thousands, and David and his men were proceeding in the back with Achish.

Then the commanders of the Philistines said, “What are these Hebrews doing here?” And Achish said to the commanders of the Philistines, “Is this not David, the servant of Saul the king of Israel, who has been with me these days, or rather these years, and I have found nothing at all suspicious in him since the day he deserted to me to this day?”

But the commanders of the Philistines were angry with him, and the commanders of the Philistines said to him, “Make the man go back, so that he will return to his place where you have assigned him, and do not let him go down to battle with us, or in the battle he may become an adversary to us. For how could this man find favor with his lord? Would it not be with the heads of these men?