1 Samuel 26:7-11

So David and Abishai went right into Saul’s camp and found him asleep, with his spear stuck in the ground beside his head. Abner and the soldiers were lying asleep around him. “God has surely handed your enemy over to you this time!” Abishai whispered to David. “Let me pin him to the ground with one thrust of the spear; I won’t need to strike twice!” “No!” David said. “Don’t kill him. For who can remain innocent after attacking the LORD’s anointed one? Surely the LORD will strike Saul down someday, or he will die of old age or in battle. The LORD forbid that I should kill the one he has anointed! But take his spear and that jug of water beside his head, and then let’s get out of here!”