As I have surveyed the life of Hezekiah, I have drawn details from 2 Kings, 2 Chronicles, and Isaiah. To have the most complete understanding of Hezekiah's life, using all three sources is necessary. Though at times, trying to get a handle on how the details are presented in the three sources can be confusing.
For example, when we look at Isaiah 38-39, it might be natural to assume that chronologically, chapters 38 and 39 occur after chapters 36 and 37. After all, that's how it's written, right? Well, there are a few indicators in those chapters, 38 and 39, that suggest that the correct chronology of Isaiah is 38, 39, 36, 37.
Here is the best one: 38:6 - "I will deliver you and this city from the hand of the king of Assyria." This promise of protection and deliverance clearly occurred before the angel of the LORD defeated the Assyrian army and before Sennacherib broke camp and returned to Nineveh, both of which were already detailed in Isaiah chapter 37.
So, let's "turn back time" and review Isaiah 38-39, which actually took place before the things we have already discussed. As you will see, these chapters actually give some explanation of why chapters 36 and 37 occurred.
All three records - 2 Kings 20, 2 Chronicles 32, and Isaiah 38 - say that Hezekiah was ill and at the point of death. And they all record Hezekiah's prayer, which resulted in the LORD mercifully restoring Hezekiah's health. In response to Hezekiah's prayer the LORD said three things would occur:
1. Hezekiah would go up to the Temple three days later,
2. The LORD would add 15 years to Hezekiah's life, and
3. The LORD would deliver Hezekiah and the city of Jerusalem from Assyria.
In contrast to his father's rejection of a sign from the LORD (Isa. 7:11-12), upon hearing of his restoration and 15-year life extension, Hezekiah asked for a sign. Isaiah inquired as to which Hezekiah would prefer as a sign from the LORD, that the sun would move forward or backward.
Hezekiah realized that the shadow of the sun moving forward may not be a clear sign. After all, the sun naturally moves forward. So, he asked for the shadow of the sun to move backward. In other words, he asked for time to be turned back.
Here is the LORD's response: "I will make the shadow cast by the sun go back the ten steps it has gone down on the stairway of Ahaz." It isn't clear how this was done, but God, who put all things in motion, is able to reverse things and still keep all things in order. Don't forget, during the days of Joshua the sun had already stood still over Gibeon (Joshua 10:13). It's not something that happens every day, or even often, but God, as it pleases Him, does what appears to be impossible to us. "So the sunlight went back the ten steps it had gone down (Isa. 38:8)."
Interestingly, the account of Hezekiah's punitive illness in 2 Chronicles is abbreviated, apparently for the purpose of highlighting the reason for both his condition and the perilous situation of Jerusalem - his pride.
Once again, the chronology can be confusing. By the order of presentation in 2 Chronicles 32:24-25, one may get the impression that the LORD healed Hezekiah and still his heart was proud. However, like we did in sorting out chapters 36-38 of Isaiah, we need to examine the complete presentation. In doing this we will see that as a result of Hezekiah's pride, the LORD's wrath was on him and on Judah and Jerusalem (2 Chr 32:26), which clearly occurred before the LORD restored Hezekiah. As was pointed out above, one of the elements of Hezekiah's restoration was that the LORD would deliver Hezekiah and Jerusalem from Assyria.
It shouldn't surprise the reader that Hezekiah struggled with pride. The elements were clearly in place for pride to be a potential problem: In addition to being the king, he had very great riches, built many buildings and villages, and acquired great numbers of flocks and herds. "He succeeded in everything he undertook (2 Chron 32:30)." Hezekiah started out well, restoring Passover and removing the high places, but his wealth and success created a proud heart in him.
Thankfully, the LORD knows how to bring about humility. And in Hezekiah's case, a punitive illness and potential destruction of Jerusalem were the LORD's instruments of merciful correction in Hezekiah's life.
That is the back story to the Assyrian siege of Jerusalem.
The order of events as I understand it is:
1. Hezekiah was proud
2. God sent Assyria and a punitive illness as a form of discipline
3. Hezekiah repented
4. God restored Hezekiah
5. God delivered Hezekiah and Jerusalem from the Assyrian threat.