I Samuel 29:8 And David said unto Achish, But what have I done? and what hast thou found in thy servant so long as I have been with thee unto this day, that I may not go fight against the enemies of my lord the king?
David continues playing his game of being on the side of the Philistines. He has deceived the king but the warriors and generals know better. They do not trust David.
David has offered to go out and fight for the enemies of Achish. He really could never do this. It would have violated his conscience but he needed to continue playing the part for now.
Soon David will be home leading his own kingdom but for now he is still in hiding.