Blue  Ch 18 v13- Ch 19  2 Kings

The king of Assyria wants to invade Jerusalem so his field commander is sent to scare them, using things like factual truth from stories about their previous military wins in an attempt to defeat their emotional and mental strength and to bring Jerusalem under Assyrian control.  He also used religion.  The field commander took what they knew about the LORD then he sought to act like the LORD was on his side and not theirs, even going so far as to declare that God had told him to come and destroy their country.  Then the field commander attacked their king by sowing doubt about their leader.  Warning them not to trust Hezekiah who had been persuading them to trust in the LORD for deliverance, also accusing Hezekiah of being misleading, before going over all the countries the Assyrians had successfully took victory over.  But where the guy blasphemed was when he pulled a Mike Tyson in verse 35 "Who of all the gods of these countries has been able to save his land from me?  How then can the LORD deliver Jerusalem from my hand?"

The matter ended up at the prophet's door where Isaiah assured, per Word of the LORD, "Do no be afraid of what you have heard - those words with which the underlings of the king of Assyria have blasphemed me.  Listen!  I am going to put such a spirit in him that when he hears a certain report, he will return to his own country, and there I will have him cut down with the sword."

This was received well and the words believed but it was tested because Hezekiah got another threat only this time it was a letter sent to him not long after the prophetic word, which immediately sent Him into prayer!  "Now, O LORD God our God, deliver us from his hand, so that all kingdoms on earth may know that You alone, O LORD, are God."

As Hezekiah prays a long declarative prophetic prayer we learn:

v30 Once more a remnant of the house of Judah will take root below and bear fruit above.  v31 For out of Jerusalem will come a remnant, and out of Mount Zion a band of survivors.  The zeal of the LORD Almighty will accomplish this.  v34 I (LORD) will defend this city and save it, for My sake and for the sake of David My servant.

And so we see prophecy come to pass:

v35 That night the Angel of the LORD went out and put to death 185,000 men in the Assyrian camp.  v36 So Sennacherib king of Assyria broke camp and withdrew.  He returned to Nineveh and stayed there.  v37 One day, while he as worshipping in the temple of his god Nisroch, his sons...put him down with the sword.