1 Samuel 26:7-11 NIV

7 So David and Abishai went to the army by night, and there was Saul, lying asleep inside the camp with his spear stuck in the ground near his head. Abner and the soldiers were lying around him.
8 Abishai said to David, "Today God has delivered your enemy into your hands. Now let me pin him to the ground with one thrust of my spear; I won't strike him twice."
9 But David said to Abishai, "Don't destroy him! Who can lay a hand on the LORD's anointed1 and be guiltless?2

References for 1 Samuel 26:9

10 As surely as the LORD lives," he said, "the LORD himself will strike3 him; either his time4 will come and he will die,5 or he will go into battle and perish.

References for 1 Samuel 26:10

11 But the LORD forbid that I should lay a hand on the LORD's anointed. Now get the spear and water jug that are near his head, and let's go."