Ezekiel 33:6

But if the watchman see the sword come, as the host of invaders approaches, and blow not the trumpet, deliberately neglecting this solemn duty, and the people be not warned, since they relied upon his giving the signal: if the sword come and take any person from among them, he is taken away in his iniquity, being guilty of negligence in not maintaining constant watchfulness, as those surrounded by enemies ought to do, but his blood will I require at the watchman's hand, he would be held responsible for his neglect in warning the people who relied upon him. Note that the meaning of the picture is here already intimated.