Complete Commentary on the Whole Bible, by Matthew Henry, at sacred-texts.com
(v. 1-19) Hezekiah's good reign in Judah.
(v. 20-36) Hezekiah's sacrifice of atonement.
2 Chronicles 29:1
When Hezekiah came to the crown, he applied at once to work reform. Those who begin with God, begin at the right end of their work, and it will prosper accordingly. Those that turn their backs upon God's ordinances, may truly be said to forsake God himself. There are still such neglects, if the word be not duly read and opened, for that was signified by the lighting the lamps, and also if prayers and praise be not offered up, for that was signified by the burning incense. Neglect of God's worship was the cause of the calamities they had lain under. The Lord alone can prepare the heart of man for vital godliness: when much good is done in a little time, the glory must be ascribed to him; and all who love him or the souls of men, will rejoice therein. Let those that do good work, learn to do it well.
2 Chronicles 29:20
As soon as Hezekiah heard that the temple was ready, he lost no time. Atonement must be made for the sins of the last reign. It was not enough to lament and forsake those sins; they brought a sin-offering. Our repentance and reformation will not obtain pardon but in and through Christ, who was made sin, that is, a sin-offering for us. While the offerings were on the altar, the Levites sang. Sorrow for sin must not prevent us from praising God. The king and the congregation gave their consent to all that was done. It is not enough for us to be where God is worshipped, if we do not ourselves worship with the heart. And we should offer up our spiritual sacrifices of praise and thanksgiving, and devote ourselves and all we have, as sacrifices, acceptable to the Father only through the Redeemer.