1 Samuel 26:8-12

Then Abishai said to David, “Today God has handed your enemy over to you; now then, please let me pin him with the spear to the ground with one thrust, and I will not do it to him a second time.”

But David said to Abishai, “Do not kill him, for who can reach out with his hand against the Lord’s anointed and remain innocent?”

David also said, “As the Lord lives, the Lord certainly will strike him, or his day will come that he dies, or he will go down in battle and perish.

The Lord forbid that I would reach out with my hand against the Lord’s anointed! But now please take the spear that is at his head and the jug of water, and let’s go.”

So David took the spear and the jug of water that were at Saul’s head, and they left; and no one saw or knew about it, nor did anyone awaken, for they were all asleep, because a deep sleep from the Lord had fallen on them.