Charles Ellicott Commentary 2 Chronicles 29:31

"Then Hezekiah answered and said, Now ye have consecrated yourselves unto Jehovah; come near and bring sacrifices and thank-offerings into the house of Jehovah. And the assembly brought in sacrifices and thank-offerings; and as many as were of a willing heart [brought] burnt-offerings." — 2 Chronicles 29:31 (ASV)

THE CONSECRATION COMPLETED BY ADDITIONAL SACRIFICES
(2 Chronicles 29:31–36).

Answered and said. —See 1 Chronicles 12:17. The phrase is used as we would use it in Exodus 4:1; 2 Kings 7:13.

You have consecrated ... —Literally, you have filled your hand for Jehovah, a phrase used for the consecration of priests (Leviticus 7:37). This phrase is here addressed to the whole assembly, as the following words prove (unless the text is unsound). The congregation, as well as the sacerdotal order, had consecrated themselves anew to Jehovah by their presence and participation in the previous solemnities.

Others suppose that these words are spoken to the priests only, and that then the king turns to the congregation with the words “Come near,” etc. (There should be a semicolon after “the Lord.”)

Sacrifices and thank offerings (zebahîn we thôdôth). —The first word means “thank-offerings” (= zébahîm shelamîm); the second, a particular type of thank-offering, apparently accompanied by a special kind of psalms called tôdôth (“thanksgivings”). “Sacrifices and thank-offerings” therefore means “sacrifices, that is, thank-offerings” (Leviticus 7:16, for the three kinds of thank-offerings).

As many as were of a free heart. —Literally, Every free-hearted one (1 Chronicles 29:6; 1 Chronicles 29:9).

Burnt offerings were a token of greater self-denial and disinterestedness than thank-offerings, because they were wholly consumed on the altar, whereas the worshippers feasted upon the latter.