1 Samuel 21:13-15

13So when David was with them, he pretended to be crazy. He made marks with his fingers on the doors of the city's gate. He let water run out of his mouth and go down his beard.

14King Achish said to his servants, ‘Look at this man! He is completely crazy! Why did you bring him to me?

15I have enough fools around me already. I do not need to see this crazy man as well. Keep him away from my house.’