But Micaiah said, "As the LORD lives, what my God says, that I will speak."
2 Chronicles 18:13
This is an interesting account of God's sovereign work. It is one of the significant moments when a king in Israel is detailed in 2 Chronicles. And the only reason is because this was also a significant event in the life of Jehoshaphat, king of Judah. It came about because of a political expediency.
Jehoshaphat made an alliance with Ahab through marriage. And the king of Judah traveled to Samaria to celebrate this with Ahab. While there, Ahab tries to convince him to go into a military campaign against Syria. And we get insight into Ahab's spiritual condition at that time. Ahab has 400 prophets at his disposal. It is important to take note that they are referred to as "his" prophets. And they tell him victory against Syria is a sure thing. They are not the Lord's prophets. They are Ahab's prophets.
Jehoshaphat insists to hear from a prophet of Yahweh. Micaiah is summoned. He eventually warns Ahab that he will die in this battle. The cost of this prophecy for Micaiah was imprisonment. But Micaiah stayed true to the word that God had given him.
In the end, God is proven right. Ahab is killed in battle even though he tried to disguise himself and divert attention to Jehoshaphat as the king in command. Jehoshaphat is miraculously delivered by God in spite of his foolish compromises. And the words of Micaiah are proven true... faithful to the message of God.