See 1 Kings 22:8. Ahab implies that he believes Micaiah to have spoken out of pure malevolence, without any authority for his prediction from God. By implication he invites Jehoshaphat to disregard this pseudo-prophecy, and to put his trust in the unanimous declaration of the 400. Micaiah, therefore, proceeds to explain the contradiction between himself and the 400, by recounting another vision.
Related Commentaries of 1 Kings 22:18
1 Kings 22:18
18 And the king of Israel said unto Jehoshaphat, Did I not tell thee that he would prophesy no good concerning me, but evil?