| Gill's Exposition of the Entire Bible Then said Achish to his servants, lo, you see the man is mad,.... Which he said, as willing his servants should think so, and therefore rather the object of their pity than of their rage and malice; or as really believing he was so, which he and they might conclude not merely from these his actions, before described, which they might judge real and not feigned; but they might suppose this was truly his case, brought upon him by the ill usage of Saul, who pursuing him from place to place, and sending after him to take away his life, had really brought him to distraction; and this they might rather conclude from his coming to Gath, an enemy's country, and whose champion he had slain, and many others of them; which it might be thought no man in his senses would have done: wherefore then have ye brought him to me? for if he was brought to be employed in his service, he seemed very unfit for it, whether in the camp, or in the court; and if to be tried and condemned as an enemy, since he was a madman, he was rather to be pitied.
Keil and Delitzsch Biblical Commentary on the Old TestamentBy this dissimulation David escaped the danger which threatened him; for Achish thought him mad, and would have nothing to do with him. "Wherefore do ye bring him to me? Have I need of madmen, that ye have brought this man hither to rave against me? Shall this man come into my house?" Thus Achish refused to receive him into his house. But whether he had David taken over the border, or at any rate out of the town; or whether David went away of his own accord; or whether he was taken away by his servants, and then hurried as quickly as possible out of the land of the Philistines, is not expressly mentioned, as being of no importance in relation to the principal object of the narrative. All that is stated is, that he departed thence, and escaped to the cave Adullam.
Geneva Study BibleThen said Achish unto his servants, Lo, ye see the man is mad: wherefore then have ye brought him to me?
King James Translators' Notesis mad: or, playeth the mad man
Matthew Henry's Concise Commentary21:10-15 God's persecuted people have often found better usage from Philistines than from Israelites. David had reason to put confidence in Achish, yet he began to be afraid. His conduct was degrading, and discovered wavering in his faith and courage. The more simply we depend on God, and obey him, the more comfortably and surely we shall walk through this troublesome world. | 
