1 Samuel 26:7-9

7 So David and Abishai came to the people by night: and, behold, Saul lay sleeping within the trench, and his spear stuck in the ground at his bolster: but Abner and the people lay round about him.

8 Then said Abishai to David, God hath delivered thine enemy into thine hand this day: now therefore let me smite him, I pray thee, with the spear even to the earth at once, and I will not smite him the second time.

9 And David said to Abishai, Destroy him not: for who can stretch forth his hand against the LORD’s anointed, and be guiltless?