Assyria has taken all the lands of Judah, save the capital, Jerusalem (Isaiah 36:1). A great army comes to the city, with a general named Rabshakeh (a type of Satan). He meets with the diplomats outside the city (Isaiah 36:2-3). He challenges their position, their obstinate decision to keep a defense, tells them that Egypt will be no help, scoffs at their numbers, and blasphemes the name of the Lord (Isaiah 36:4-10).
The diplomats from Jerusalem ask the general to speak in the Syrian tongue so that the people behind them listening from the city walls won't hear them (Isaiah 36:11). Rabshakeh continues speaking in the language of the Jews, and actually starts yelling, so the audience can hear him (Isaiah 36:12-13).
He's trying to undermine the faith in their king and in God, and tries to reason with them saying that if they willingly submit to his army, that they will be taken to a good land (Isaiah 36:14-17). He also starts boasting about how the gods of the other lands that the Assyrians have conquered have failed them, and that Jehovah would be no different (Isaiah 37:18-20).
The diplomats don't respond, and quickly return to Hezekiah to tell him everything that happened (Isaiah 36:21-22).
Hezekiah is just as worried as the diplomats are, and goes to the temple to pray for strength (Isaiah 37:1). Perhaps as a result of his visit, he sees that the solution is beyond him, and he sends the same messengers to the prophet Isaiah (Isaiah 37:2-5).
I think that there's a connection between these two events: the king going to the temple and then to the prophet. I think that it strengthened his faith in the trials to come. He knew that the Lord could deliver them, but he was unsure of how to proceed.
I like the king's message to Isaiah: "there is not strength to bring forth." He is aware of his limitations (Isaiah 37:3), and admits them to the prophet.
The Lord's response is amazing. "Thus saith the Lord, Be not afraid of the words that thou hast heard." His first counsel is to not fear. Here is a nation, an island among nations, whose borders have completely falling and been destroyed, and an army camps round about, and God tells them to firstly, fear not.
The Lord promises that he (assuming the king, or Rabshakeh) will return to his own land, which he does (Isaiah 37:6-8). During this time, Rabshakeh sends a letter to Hezekiah, by messengers, and again says that his god will not be able to prevent his downfall. This is again another example of Rabshakeh acting as a type of Satan. The devil uses many tactics and mediums to discourage the people. Also, if there is only one point he can get across (the summary of the message he sent, which would be concise), it is his desire to undermine their faith in God (which is the first principle and action of the Gospel).
The king, who wants more help from the Lord, goes back to the temple, this time bringing the letter with him. At this point, the Lord has only promised through his prophet that the king would leave. There is still the matter of the salvation of the city. This must have been a hard trial for the king.
This time, we get to see part of the prayer that he himself delivered. He presents his testimony to the Lord, asks Him to see the words spoken against Him, summarizes the political situation that he finds themselves in, acknowledges the Lord's ways, and asks for a blessing from the Lord's hand (Isaiah 37:14-20).
The Lord answers the king's prayer through the prophet, and in style consistent of Isaiah, he talks of the scenario and future events concerning multiple parties: He recounts the hearts and thoughts of the king of Assyria [Isaiah 10:12-4], He speaks of the unrighteous inhabitants that were swept off by His power and confirms that He used the Assyrians to accomplish that work [Isaiah 8:6-8].
He says that he will turn back the king, and that Judah will eat of the good of the land and be safe. And finally, the pinnacle of the prophecy, the Lord proclaims that the army of Assyria will not advance neither one man nor one arrow into the city – they will return the way they came, and He will defend it for his sake, and for a testimony, just as the king had prayed (Isaiah 37:33-35).
And so it was. "The angel of the Lord" smote 185,000 Assyrians in one night, and the rest of them left.
I think there's a lot of cool things to learn from this story. For one, I think there's a great lesson in how the lesser parts not committed to the Lord fell round about, finally exposing the core that was faithful (all the cities but Jerusalem fell).
In any battle if the enemy can convince them to surrender, so much the better. A discouraging word can be so effective, and a long campaign would occupy many resources.
The elect king was without ally or assistance, save from the Lord, who counseled him to keep the faith.
Furthermore, I imagine this siege lasted some time, showing that determination in the face of adversity may be required of us.
The good king humbled himself, worshiped the Lord, did what he could to strengthen his faith, and looked to the prophet for counsel. Likewise, I can look to the resources available and look to the scriptures.
In the end, Hezekiah's deliverance was provided completely by the hand of the Lord, the king had no part of it.