2-kings 18:3

He did that which was right in the sight of the Lord - In chap. 29 of the second book of Chronicles, we have an account of what this pious king did to restore the worship of God. He caused the priests and Levites to cleanse the holy house, which had been shut up by his father Ahaz, and had been polluted with filth of various kinds; and this cleansing required no less than sixteen days to accomplish it. As the passover, according to the law, must be celebrated the fourteenth of the first month, and the Levites could not get the temple cleansed before the sixteenth day, he published the passover for the fourteenth of the second month, and sent through all Judah and Israel to collect all the men that feared God, that the passover might be celebrated in a proper manner. The concourse was great, and the feast was celebrated with great magnificence. When the people returned to their respective cities and villages, they began to throw down the idol altars, statues, images, and groves, and even to abolish the high places; the consequence was that a spirit of piety began to revive in the land, and a general reformation took place.

He did that which was right ... - This is said without qualification of only three kings of Judah, Asa 1 Kings 15:11, Hezekiah, and Josiah 2 Kings 22:2. See some details of Hezekiah's acts at the commencement of his reign in 2 Chronicles 29, etc. It is thought that his reformation was preceded, and perhaps caused, by the prophecy of Micah recorded in Jeremiah 26:18; Micah 3:12.