Does he think he can plan and win a war with nothing but words? Who is going to help him, now that he has turned against the king of Assyria?
The LORD helped Hezekiah, so he was successful in everything he did. He even rebelled against the king of Assyria, refusing to be his servant.
Make them work so hard that they won't have time to listen to these lies.
Be sure you have sound advice before making plans or starting a war.