1 Samuel 21:10-15

10And David arose, and fled that day from before Saul, and went to Achish the king of Gath. 11And the servants of Achish said to him, Is not this David the king of the land? did they not sing one to another of him in dances, saying, Saul has smitten his thousands, and David his ten thousands? 12And David took to heart these words, and was much afraid of Achish the king of Gath. 13And he changed his behaviour before them, and feigned himself mad in their hands, and scratched on the doors of the gate, and let his spittle fall down on his beard. 14And Achish said to his servants, Behold, ye see the man is mad: why did ye bring him to me? 15have I lack of madmen, that ye have brought this one to rave in my presence? shall this [man] come into my house?