Jehoshaphat was afraid, so he decided to seek the Lord’s advice. He decreed that all Judah should observe a fast.

Then the king turned around and pronounced a blessing over the whole Israelite assembly as they stood there.

the prophet Jehu son of Hanani confronted him; he said to King Jehoshaphat, “Is it right to help the wicked and be an ally of those who oppose the Lord? Because you have done this the Lord is angry with you!

But Josiah did not turn back from him; he disguised himself for battle. He did not take seriously the words of Necho which he had received from God; he went to fight him in the Plain of Megiddo.