1 Samuel 21:10-15

So David escaped from Saul and went to King Achish of Gath. But the officers of Achish were unhappy about his being there. “Isn’t this David, the king of the land?” they asked. “Isn’t he the one the people honor with dances, singing, ‘Saul has killed his thousands, and David his ten thousands’?” David heard these comments and was very afraid of what King Achish of Gath might do to him. So he pretended to be insane, scratching on doors and drooling down his beard. Finally, King Achish said to his men, “Must you bring me a madman? We already have enough of them around here! Why should I let someone like this be my guest?”