1 Samuel 26:6-9

6Then answered David and said to Ahimelech the Hittite, and to Abishai the son of Zeruiah, brother to Joab, saying, Who will go down with me to Saul to the camp? And Abishai said, I will go down with thee. 7So David and Abishai came to the people by night: and, behold, Saul lay sleeping within the place of the wagons, with his spear stuck in the ground at his head; and Abner and the people lay round about him. 8Then said Abishai to David, God hath delivered up thine enemy into thy hand this day: now therefore let me smite him, I pray thee, with the spear to the earth at one stroke, and I will not smite him the second time. 9And David said to Abishai, Destroy him not; for who can put forth his hand against Jehovah’s anointed, and be guiltless?