Hezekiah, King of Judah, was under a serious threat from Rabshakeh and the Assyrians. Wisely, he didn't look for help from Egypt, nor from any other human source, he went to God for deliverance. And, as he made his way to the temple, he sent for a prophet of God: Isaiah. Hezekiah accurately figured that God would not sit idly by after Rabshakeh and his royal master had spoken so blasphemously against Him.
Now, through Isaiah, Hezekiah found out that Rabshakeh was going to leave him alone temporarily, and that afterward the Assyrians would be defeated (II Kings 19:7). The first part of that prophecy was verified when the Assyrian leader (ultimately Sennacherib) sent a threatening letter to Hezekiah trying to intimidate him into surrendering, while at the same time, they (the Assyrians) packed up to leave. Hezekiah did what we should all do with all our problems... he took it to the Lord in prayer (II Kings 19:15 -19).
Hezekiah literally took the letter and opened it up in the temple. He laid it out in there for God to see (II Kings 19:14). And, God responded vigorously and favorably on Hezekiah's behalf. One of God's angelic soldiers came down and killed 185,000 Assyrians who were camped outside of Jerusalem. Naturally, without an army, Sennacherib wasn't much of a threat. So, he fled home to Nineveh, capitol of Assyria, where he was murdered by 2 of his own sons while he was worshipping his powerless god, Nisroch.