1. Hezekiah orders the house of the Lord to be cleansed.
2 Chronicles 28:24 Shut up the doors
‘ [Ahaz] caused the Divine worship to be totally suspended; and they continued shut till the beginning of the reign of Hezekiah, one of whose first acts was to reopen them, and thus to restore the Divine worship, 2 Chronicles 29:3.’ (Clarke’s Commentary on the Bible)

2 Chronicles 29:3-5 Hezekiah
‘Hezekiah (meaning ‘whom Jehovah has strengthened’) was 25 years old when he commenced his 29 year reign upon the throne. Immediately upon becoming king, he focused his energy on the temple, causing the priesthood bearers to repair it and cleanse it after years of abuse by unrighteous kings. His directive was to ‘ sanctify now yourselves, and sanctify the house of the Lord God of your fathers’ (2 Chronicles 29:5).’ (Richard J Allen, Study Commentary on the Old Testament).
2 Chronicles 29:8-9 He hath delivered them to trouble, to astonishment
‘He probably refers here chiefly to that dreadful defeat by the Israelites in which a hundred and twenty thousand were slain, and two hundred thousand taken prisoners; see the preceding chapter, 2 Chronicles 28:6-8′ (Clarke’s Commentary on the Bible)
2 Chronicles 30:20 The Lord….healed the people
‘Rehoboam rejected the counsel which required him to humble himself and to serve others. Instead, he chose to reign over Israel with a very heavy hand, thus causing a great division into the northern Kingdom of Israel and the southern Kingdom of Judah. (See 1 Kgs. 12:20)
For the next 220 years the people generally set aside their sacred covenants, thus wandering in the ways of the world. Then a young man named Hezekiah began to reign in Judah. “And he did that which was right in the sight of the Lord,” and “He trusted in the Lord God of Israel.” (2 Kgs. 18:3, 5)
Hezekiah gathered together the priesthood bearers of the day and said, “Hear me, ye Levites, sanctify now yourselves, and sanctify the house of the Lord God of your fathers, and carry forth the filthiness out of the holy place.” (2 Chr. 29:5) “Be not ye like your fathers, and like your brethren, which trespassed against the Lord God … but yield yourselves unto the Lord, … and serve the Lord your God.” ( 2 Chr. 30:7–8)

In response to this assertive leader, who was supported by the prophet Isaiah, “the Lord hearkened to Hezekiah, and healed the people” (2 Chr. 30:20) and “in their set office they sanctified themselves in holiness” (2 Chr. 31:18)
From King Hezekiah, as from King Benjamin (see Mosiah 2 Mosiah 3 Mosiah 4 and Mosiah 5) we can learn a very positive lesson on leadership: circumstances do not always need to remain the same. ‘ (Spencer J Condie, General Conference, April 1990)
2. The Assyrians invade the kingdom of Judah. Isaiah and Hezekiah pray for help, and an angel of the Lord destroys much of the Assyrian army.
2 Chronicles 32:1 After these things
‘God did not permit this pious prince to be disturbed till he had completed the reformation which he had begun.’ (Clarke’s Commentary on the Bible)

Hezekiah’s Tunnel
‘As the Assyrians moved towards Jerusalem, Hezekiah has prepared for a long siege. Second Kings notes, ‘how he made a pool, and a conduit, and brought water into the city’ (2 Kings 20:20), meaning he ‘stopped the upper watercourse of Gihon, and brought it straight down to the west side of the city of David’ (2 Chronicles 32:30), resulting in the remarkable technological feat known as Hezekiah’s tunnel. This tunnel brought water from the Gihon spring to the Pool of Siloam, providing safer and increased access to water within the city walls. Along with fortifications, this tunnel was presumably part of the preparations for the Assyrian attack described in 2 Chronicles 32:3-5.’ (Dana M Pike and Richard Holzapfel, Jehovah and the World of the Old Testament)
Sennacherib
“Hoping to avoid a direct confrontation when he saw that Sennacherib was preparing to attack Judah, Hezekiah sent Sennacherib a substantial tribute of gold and silver, including most, if not all, of the palace and temple treasuries. He even had the gold plating taken off the temple doors and pillars. (See 2 Kgs. 18:13-16.) But Sennacherib wanted more; he demanded absolute submission, and he knew that Hezekiah was one of the leaders in the revolt against Assyrian authority. He wanted nothing less than the unconditional surrender of Jerusalem, and he wanted her king still alive, so that he could humiliate, torture, and finally slowly impale King Hezekiah upon a pointed stake, just as he had done to the rebel kings of the Philistines.” (Victor L. Ludlow, Isaiah: Prophet, Seer, and Poet [Salt Lake City: Deseret Book Co., 1982], 319)
2 Chronicles 32:18 Then they cried with a loud voice in the Jews’ speech
3. Josiah and his people covenant to serve the Lord.
Josiah
world, to believe the history of the servants of God more than in this age; for now the people generally require a vast amount of evidence. The testimony of a dozen witnesses is scarcely regarded.’ (Orson Pratt,Evidences of the Bible)