1 Kings 21:20

And Ahab said to Elijah, Hast thou found me, O mine enemy? The implication was that Elijah was always endeavoring to oppose the king and to thwart his purposes. And he, with all the frank fearlessness of God's messenger, answered, I have found thee, because thou hast sold thyself to work evil in the sight of the Lord. Ahab had so abandoned himself to wickedness that he had become its slave.