David’s protest is an appropriate expression of displeasure in reaction to Achish’s command.1 It could be an attempt on his part to make it appear as if he is truly loyal to Achish and the Philistines. If he agrees with their assessment and goes home without any word of protest then he will have seemingly vindicated them.2 He could also be trying to find out more information from Achish, worried perhaps that reports of his activities in the Negeb may have reached their ears.3 It is of course also possible that he was simply really keen on fighting in the battle, confident that the LORD would grant him a great victory against the Philistines if he was to attack from the rear.
8 And David said to Achish, “But what have I done? What have you found in your servant from the day I entered your service until now, that I may not go and fight against the enemies of my lord the king?”