1 Samuel 26:6-9

6Then David answered, and said to Ahimelech the Hittite and to Abishai the son of Zeruiah, brother of Joab, saying, “Who will go down with me to Saul in the camp?” And Abishai said, “I will go down with you.”

7So David and Abishai came to the people by night; and there Saul lay sleeping within the camp, with his spear stuck in the ground by his head. And Abner and the people lay all around him.

8Then Abishai said to David, “God has delivered your enemy into your hand this day. Now therefore, please, let me strike him at once with the spear, right to the earth; and I will not have to strike him a second time!”

9But David said to Abishai, “Do not destroy him; for who can stretch out his hand against the Lord’s anointed, and be guiltless?”