“Then said Achish unto his servants, Lo, ye see the man is mad: wherefore then have ye brought him to me?”
King James Version (KJV)
21:12 Was afraid - Lest either their revenge or policy should prompt them to kill him. Perhaps he was the more apprehensive, because he wore Goliath's sword, which was probably well known at Gath. He now learned by experience what he afterward taught us, #Psal 118:9|. It is better to trust in the Lord, than to put any confidence in princes.
21:15 Mad men - It is highly probable, Achish was aware, that this madness was counterfeit. But being desirous to preserve David, he speaks as if he thought it real.