1 Samuel 21:9-15 - David Goes To Gath
9 So the priest said, "The sword of Goliath the Philistine whom you killed in the valley of Elah [is] here, wrapped in a cloth behind the ephod. If you want to take it for yourself, [then] take it, for there is no other except it here." And David said, "There is none like it; give it to me."
10 So David got up and fled on that day from the presence of Saul, and he came to Achish the king of Gath. 11 The servants of Achish said to him, "[Is] not this David the king of the land? [Is] it not for this [one] that they sang in the dances, saying, 'Saul killed his thousands, but David his ten thousands?'"
12 {David took these words seriously} and {felt severely threatened by} Achish the king of Gath. 13 So he changed his behavior {before them} and pretended to be mad {in their presence}. He made scratches on the doors of the gate and let his saliva run down into his beard.
14 Then Achish said to his servants, "Look, you see a madman! Why did you bring him to me? 15 Do I lack madmen that you have brought this one to act like a madman before me? Should this one enter my household?"