1 Samuel 26:7-11

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. 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. And David said to Abishai, Destroy him not: for who can stretch forth his hand against the LORD's anointed, and be guiltless? David said furthermore, As the LORD liveth, the LORD shall smite him; or his day shall come to die; or he shall descend into battle, and perish. The LORD forbid that I should stretch forth mine hand against the LORD's anointed: but, I pray thee, take thou now the spear that is at his bolster, and the cruse of water, and let us go.