When Hezekiah hears the message, he freaks out, tears his clothes, and does the whole sack-cloth-and-wailing routine.
He sends Eliakim, Shebna, and the senior priests to take counsel from Isaiah.
Isaiah tells them to tell Hezekiah not to worry. God's going to punish Sennacherib by putting a spirit in him, so that he'll hear a rumor and return to his own land, where he'll end up getting killed.
The Rabshakeh brings Isaiah's message to Sennacherib, who is occupied with fighting other battles, elsewhere.
Sennacherib tells him to send another snarky message, asking Hezekiah how he expects his God to resist Assyria when the Assyrian kings have beat down so many other gods. And he gives examples of his various triumphs—it's a classic example of arrogant bad-guy talk.
Hezekiah gets Sennacherib's message, which he then takes to the Temple and spreads it out before God.
Hezekiah prays for God to save Jerusalem, telling him about how arrogant Sennacherib's boasts are, and also about how he has burned the idols of other people's gods. Hezekiah suggests that it would be good P.R. for God to defeat the Assyrians, since all the nations would then know that God was real.
Involuntary Nose Piercing
Soon thereafter, Isaiah relays a message from God to Hezekiah.
God says that Assyria is like a haughty Mean Girl, tossing her hair in front of God's daughter, Zion.
He angrily rebukes the Assyrian King for his boasts, talking about how he's cut down the tallest trees in Lebanon and dried up Egypt with his own foot (and things like that).
God notes that he, alone, has allowed Sennacherib to attack and plunder all these cities and lands. He knows when Sennacherib is asleep and awake, and when he's been bad or good… and he's been very bad, indeed.
God says he'll put a hook into Sennacherib's nose and turn him right around, sending him back to Assyria.
Before ending his prophecy, God offers words of reassurance to Judah: Jerusalem won't fall to Assyria's siege, a remnant of Judah will survive, and Sennacherib will return to his home.
The next day, this is all fulfilled. The angel of God slaughters 185,000 Assyrian troops during the night.
Sennacherib returns to Assyria, but his sons plot against him and kill him, leaving one of them to become his successor.