1 Samuel 21:15
Have I need of mad men, that ye have brought this fellow to play the mad man in my presence? shall this fellow come into my house? Have I need of mad men, that ye have brought this fellow to play the mad man in my presence? shall this fellow come into my house?
This verse belongs to the time when David was fleeing from Saul and came to the king of Gath. The speaker is Achish, king of Gath, who objects to a man he regards as mad being brought into his presence and questions why he should be admitted into his house. David was deliberately pretending to be insane, feigning madness to deceive his enemies and escape danger.
The Spirit of God led David to act in this way. As part of this pretense, spittle ran down his beard.