There were a number of prophecies against Assyria and their fall and in Isaiah 37 we see those prophecies fulfilled. In chapter 31 we read:
And the Assyrian shall fall by a sword, not of man;
and a sword, not of man, shall devour him…
In chapter 37, after Sennacherib, the leader of the Assyrians, mocks the God of Israel in his dealings with Hezekiah he leaves to attend to an uprising in the south by the king of Egypt.
Sennacherib has been very successful in his rule, as he notes to Hezekiah. Assyria has been used by God to bring his judgment on the land and Sennacherib says, “Behold, you have heard what the kings of Assyria have done to all lands, devoting them to destruction. And shall you be delivered? Have the gods of the nations delivered them, the nations that my fathers destroyed…?”
Hezekiah must be in great fear, for himself, his people, and Jerusalem. But he knows that those other gods were no gods at all. He goes to the temple and prays for God’s deliverance, and does so with the purpose that the kingdoms of earth may know that Israel’s God is truly God.
As I said, the prophecy is fulfilled and Hezekiah’s prayers are answered. In going to fight off the Egyptians, Sennacherib is dealt a grew blow, loses thousands of men, and retreats back to the capital of Ninevah.
There is an interesting comparison between these two leaders. Hezekiah goes to the temple and is heard by God and is spared. Later, after backing down following the loss of so many of his men at the hand of God’s angels, Sennacherib goes to his temple. There he is not delivered, rather he finds his end as his own sons kill him in order to seize power for themselves.
Also-in reading about this passage I found two accounts of how the 185,000 of Sennacherib’s camp were put to death. One is an account of some pesky mice that came out in the night to gnaw away at the bows and the straps of Assyrian shields, leaving that army weakened. The other is not as exciting, and records disease as the tool used to bring about their destruction.