1 Samuel 26:7-12

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. So David took the spear and the cruse of water from Saul's bolster; and they gat them away, and no man saw it, nor knew it, neither awaked: for they were all asleep; because a deep sleep from the LORD was fallen upon them.