1 Samuel 21:10

7 Now one of Saul’s servants was there that day, detained before the LORD. And his name was Doeg the Edomite, the chief shepherd for Saul.

8 Then David asked Ahimelech, “Is there not a spear or sword on hand here? For I have brought neither my sword nor my weapons with me, because the king’s business was urgent.”

9 The priest replied, “The sword of Goliath the Philistine, whom you killed in the Valley of Elah, is here; it is wrapped in a cloth behind the ephod. If you want, you may take it. For there is no other but this one.” And David said, “There is none like it; give it to me.”

10 That day David fled from Saul and went to Achish king of Gath.

11 But the servants of Achish said to him, “Is this not David, the king of the land? Did they not sing about him in their dances, saying: ‘Saul has slain his thousands, and David his tens of thousands’?”

12 Now David took these words to heart and was very much afraid of Achish the king of Gath.

13 So he changed his behavior before them and feigned madness in their hands; he scratched on the doors of the gate and let his saliva run down his beard.