Hezekiah saw Israel’s fall and knew about the warnings from Isaiah and other prophets. His first action, before he had been in power a month, was to reopen the doors of the Temple and restore the building and worship, explaining to the Levites and priests:
2 Chronicles 29:6-8 Our ancestors were unfaithful and did what was evil in the sight of the Lord our God. They abandoned the Lord and his dwelling place; they turned their backs on him. … That is why the Lord’s anger has fallen upon Judah and Jerusalem. He has made them an object of dread, horror, and ridicule, as you can see with your own eyes.
The instruction was:
2 Chronicles 29:11 My sons, do not neglect your duties any longer! The Lord has chosen you to stand in his presence, to minister to him, and to lead the people in worship and present offerings to him.