Albert Barnes Commentary 1 Kings 22:15

"And when he was come to the king, the king said unto him, Micaiah, shall we go to Ramoth-gilead to battle, or shall we forbear? And he answered him, Go up and prosper; and Jehovah will deliver it into the hand of the king." — 1 Kings 22:15 (ASV)

And he answered him... - Micaiah speaks the exact words of the 400 in such a mocking and ironic tone that the king cannot mistake his meaning or regard his answer as serious. The king’s rejoinder implies that this mocking manner was familiar to Micaiah, who had used it in some former dealings with the Israelite monarch. Hence, in part, the king’s strong feeling of dislike (Compare 1 Kings 22:8).