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.

And the king of Israel said unto Jehoshaphat,.... Plainly perceiving that the prophet foretold that he should fall in battle:

did not I tell thee that he would prophesy no good concerning me, but evil? intimating that this proceeded from spite and malice, from ill will to him and hatred of him, and was not from the Lord, and therefore not to be regarded; he had told him three years ago his life should go for letting Benhadad go; but it had not proved true, and no more would this; and Jehoshaphat being an easy man, and too credulous, believed what Ahab said of the character of this prophet, or otherwise it is not to be accounted for that he should go with him to war after such a declaration made.

But although Ahab had asked for a true word of the Lord, yet he endeavoured to attribute the unfavourable prophecy to Micah's persona enmity, saying to Jehoshaphat, "Did I not tell thee that he prophesies nothing good concerning me, but only evil (misfortune)?"

And the king of Israel said unto Jehoshaphat, Did I not tell thee that he would prophesy no good concerning me, but evil?

22:18 Evil - Nay, but what evil was it, to tell him, what would be the event, if he proceeded in his expedition, while it was in his own power, whether he would proceed, or no? The greatest kindness we can do to one that is walking in a dangerous way, is to tell him of his danger.

18-23. Did I not tell thee that he would prophesy no good concerning me, but evil?-Since Ahab was disposed to trace this unwelcome truth to personal enmity, Micaiah proceeded fearlessly to tell the incensed monarch in full detail what had been revealed to him. The Hebrew prophets, borrowing their symbolic pictures from earthly scenes, described God in heaven as a king in His kingdom. And as earthly princes do nothing of importance without asking the advice of their counsellors, God is represented as consulting about the fate of Ahab. This prophetic language must not be interpreted literally, and the command must be viewed as only a permission to the lying spirit (Ro 11:34) [Calmet].

22:15-28 The greatest kindness we can do to one that is going in a dangerous way, is, to tell him of his danger. To leave the hardened criminal without excuse, and to give a useful lesson to others, Micaiah related his vision. This matter is represented after the manner of men: we are not to imagine that God is ever put upon new counsels; or that he needs to consult with angels, or any creature, about the methods he should take; or that he is the author of sin, or the cause of any man's telling or believing a lie. Micaiah returned not the blow of Zedekiah, yet, since he boasted of the Spirit, as those commonly do that know least of the Holy Spirit's operations, the true prophet left him to be convinced of his error by the event. Those that will not have their mistakes set right in time, by the word of God, will be undeceived, when it is too late, by the judgments of God. We should be ashamed of what we call trials, were we to consider what the servants of God have endured. Yet it will be well, if freedom from trouble prove not more hurtful to us; we are more easily allured and bribed into unfaithfulness and conformity to the world, than driven to them.