Thematic Bible: Is refused permission to accompany the philistines to battle against the israelites

It happened in those days, that the Philistines gathered their armies together for warfare, to fight with Israel. Achish said to David, "Know assuredly that you shall go out with me in the army, you and your men." David said to Achish, "Therefore you shall know what your servant will do." Achish said to David, "therefore I will make you my bodyguard for ever."