Hezekiah's faith drove him to intercede for the nation of Judah. He was most interested in God's reputation and not his own personal political needs. The king of Assyria sent a missive promising invasion and demanding surrender. In that letter the Assyrians mocked the God of Israel. Assyria was an unstoppable military monster, swallowing up nations in a quest for empire. Even mighty Egypt had capitulated to Assyrian control. It did not look good for Jerusalem.
Hezekiah had no plan to thwart this invasion militarily. The army of Assyria had the city surrounded. There were no military manuevers possible to save the nation. Hezekiah's response was to worship and to trust God. He appealed to the highest power possible. He fervantly prayed to God to save His people for the greatness of His own name. He wanted the world to see that God was a God of salvation. And that prayer would bring down an empire.
The Lord answered Judah's king. And in the process an empire was humbled. The world saw what the true God did. Not one arrow flew in attack against Jerusalem. The next morning, the citizens of Jerusalem awoke to find 185,000 dead Assyrian soldiers outside their city. One angel sent from God had struck them down. The king of Assyria quietly returned home and in pagan worship in his capital was assassinated by his own sons. Assyria would threaten no one in Judah ever again. God answered the wildest request in Hezekiah's prayer: the world found out that God alone is The Lord.