1 Kings 20:38-40
38-40Then the prophet went and took a position along the road, with a bandage over his eyes, waiting for the king. It wasn't long before the king happened by. The man cried out to the king, "Your servant was in the thick of the battle when a man showed up and turned over a prisoner to me, saying, 'Guard this man with your life; if he turns up missing you'll pay dearly.' But I got busy doing one thing after another and the next time I looked he was gone."
The king of Israel said, "You've just pronounced your own verdict."
41At that, the man ripped the bandage off his eyes and the king recognized who he was—one of the prophets!