1 Samuel 26:7-11

So David and Abishai went to the army during the night, and there was Saul lying asleep inside the circle of the camp with his spear stuck in the ground by his head; and Abner and the people were lying around him. Then Abishai said to David, “God has given your enemy into your hand this day; now then, please let me strike him with the spear driving it to the ground with one stroke, and I will not strike him the second time.” But David said to Abishai, “Do not kill him, for who can put out his hand against the LORD’S anointed [king] and be guiltless (innocent)?” David also said, “As the LORD lives, most certainly the LORD will strike him [in His own time and way], or his day will come and he will die, or he will go down into battle and be carried off [dead]. The LORD forbid that I would put out my hand against the LORD’S anointed; but now take the spear that is by his head and the jug of water, and let us go.”