1 Samuel 26:15-16

And David said to Abner, Art not thou a valiant man? and who is like to thee in Israel? wherefore then hast thou not kept watch over thy lord the king? for there came one of the people in to destroy the king thy lord. This thing is not good that thou hast done. As Jehovah liveth, ye are worthy to die, because ye have not kept watch over your lord, Jehovah’s anointed. And now see where the king’s spear is, and the cruse of water that was at his head.