1 Samuel 21:13-15

MKJV(i) 13 And he changed his behavior before them, and pretended himself to be mad in their hands, and marked on the doors of the gate and let his spittle fall down on his beard. 14 Then Achish said to his servants, Lo, you see the man is mad. Why have you brought him to me? 15 Do I have need of mad men, that you have brought this one to show madness in my presence? Shall this one come into my house?