Isaiah 22:14 And it was revealed in mine ears by the LORD of hosts, Surely this iniquity shall not be purged from you till ye die, saith the Lord GOD of hosts.

2Chonicles 7:14 If my people, which are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land.
Psalm119:9 BETH. Wherewithal shall a young man cleanse his way? by taking heed thereto according to thy word.

Assyria’s siege of Jerusalem during Hezekiah {Isaiah 36:1- 37:38 & 2Ki 18:13-19:37; 2Ch 32:1-23}
The First Assyrian siege: (most commentaries point to this as the focus of Chapter 22)
Assyria took the outlying cities (filled the valley with chariots)
Hezekiah sought the LORD [2Cron 7:14]
The Angel Of The Lord killed 185,000 of the Assyrian army
The King of Assyria returned to his country in disgrace and was killed by his sons.
There is no mention of famine or men dying in Jerusalem
Because Hezekiah humbled himself before the LORD (2Cron 32:22-29) Jerusalem was healed during his days. But- .
Hezekiah was sick unto death and prayed for more years and the Lord gave him 15 (2Kings 20) but not without consequences 1) Manasseh was born and 2) the son of the king of Babylon (Assyria ruled in Babylon but the Chaldean’s also had a king) and Hezekiah showed him all the treasures of Judah - even the secrete places.
God’s response to Hezekiah’s folly of his old (added to) age (2Kings 20:16-18) - Babylon will spoil Jerusalem and have everything God had given Hezekiah.

The Second Assyrian Siege - (2Kings 21-1- 18 & 2Cron 33:1-
Manasseh only 12 years old when he began to reign - he was a wicked king undid all that his father broke down and removed.(2Kings 24:
Manasseh’s wickedness directly led to “the death of Jerusalem” 2Kings 21:10-15 & 2Kings 24:3-4) ; 2Kings 24:4 states Manasseh killed many innocent people in Jerusalem. (Human sacrifice was part of many of the religions that were allow to be followed in the high places.
Ezekiel 24:13 In thy filthiness is lewdness: because I have purged thee, and thou wast not purged, thou shalt not be purged from thy filthiness any more, till I have caused my fury to rest upon thee
The LORD brings Assyria (2Cron 33:11) and they capture Manasseh outside the city in the thorns (Isa 22:3)
But Manasseh did like his father before him did - he prayed to the LORD - (2Cron 33: 12) - He must have been taught by Hezekiah that when there seems to be no way out of trouble remember Psalm18:3 & 119:9 and 2Cron 7:14 - He greatly humbled himself before the LORD and prayed - The Lord brought him back to Jerusalem from the hand of the Assyrian king in Babylon (ruled by Assyria at this time)
Manasseh was a changed king because he learned The LORD He was God (2Cron 33:13 and HE healed their land (2Cron 33:14-17)
Manasseh received complete forgiveness from the LORD - 2Cron 33:18-19
Could it be that because Manasseh called upon the name of the LORD Jerusalem was spared from being taken by Assyria (2Kings 20:17) and led to Daniel, Hananiah, Mishael, and Azariah being able to stand before the king of Babylon in faith and knowledge of the LORD’s omnipotence? If Assyria had entered Jerusalem, history would have been quite different. But The LORD he is God and in control; remember history is His story.