1 Kings 20:13 - Ellicott's Commentary On The Whole Bible

There came a prophet. — The appearance of this unknown prophet evidently shows (see also 1 Kings 22:6-7) that Ahab’s enmity to the prophetic order was over since the great day at Carmel, and that the schools of the prophets were forming themselves again — perhaps not free from connection with the idolatry of Jeroboam, but safe from all attacks from the worshippers of Baal. It is notable that in all these political functions of prophecy Elijah does not appear, reserving himself for the higher moral and religious mission from God. Ahab receives the prophet’s message with perfect confidence and reverence; he has returned in profession to the allegiance to Jehovah, which he had, perhaps, never wholly relinquished.