That day David fled from Saul and went1 to Achish king of Gath.
References for 1 Samuel 21:10
But the servants of Achish said to him, "Isn't this David, the king of the land? Isn't he the one they sing about in their dances: " 'Saul has slain his thousands, and David his tens of thousands'?"2
References for 1 Samuel 21:11
David took these words to heart and was very much afraid of Achish king of Gath.
So he pretended to be insane3 in their presence; and while he was in their hands he acted like a madman, making marks on the doors of the gate and letting saliva run down his beard.
References for 1 Samuel 21:13
Achish said to his servants, "Look at the man! He is insane! Why bring him to me?
Am I so short of madmen that you have to bring this fellow here to carry on like this in front of me? Must this man come into my house?"