Matthew Henry on 2 Chronicles 29:20-36

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.