4 But the commanders of the Philistines were angry with him. And the commanders of the Philistines said to him, "Send the man back, that he may return to the place to which you have assigned him. He shall not go down with us to battle, lest in the battle he become an adversary to us. For how could this fellow reconcile himself to his lord? Would it not be with the heads of the men here?

Matthew Henry's Commentary on 1 Samuel 29:4

Commentary on 1 Samuel 29:1-5

(Read 1 Samuel 29:1-5)

David waited with a secret hope that the Lord would help him out of his difficulty. But he seems to have been influenced too much by the fear of man, in consenting to attend Achish. It is hard to come near to the brink of sin, and not to fall in. God inclined the princes of the Philistines to oppose David's being employed in the battle. Thus their dislike befriended him, when no friend could do him such a kindness.