A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
2 Chronicles 29:1
ch2 29:1HEZEKIAH'S GOOD REIGN. (Ch2 29:1-2)
Hezekiah began to reign, &c.--(see on Kg2 18:1). His mother's name, which, in Kg2 18:2, appears in an abridged form, is here given in full.
2 Chronicles 29:3
ch2 29:3HE RESTORES RELIGION. (Ch2 29:3-11)
in the first year of his reign, in the first month--not the first month after his accession to the throne, but in Nisan, the first month of the sacred year, the season appointed for the celebration of the passover.
he opened the doors of the house of the Lord--which had been closed up by his father (Ch2 28:24).
and repaired them--or embellished them (compare Kg2 18:16).
2 Chronicles 29:4
ch2 29:4the east street--the court of the priests, which fronted the eastern gate of the temple. Assembling the priests and Levites there, he enjoined them to set about the immediate purification of the temple. It does not appear that the order referred to the removal of idols, for objects of idolatrous homage could scarcely have been put there, seeing the doors had been shut up [Ch2 29:3]; but in its forsaken and desolate state the temple and its courts had been polluted by every kind of impurity.
2 Chronicles 29:6
ch2 29:6our fathers have trespassed--Ahaz and the generation contemporary with him were specially meant, for they "turned away their faces from the habitation of the Lord," and whether or not they turned east to the rising sun, they abandoned the worship of God. They "shut up the doors of the porch," so that the sacred ritual was entirely discontinued.
2 Chronicles 29:8
ch2 29:8Wherefore the wrath of the Lord was upon Judah and Jerusalem--This pious king had the discernment to ascribe all the national calamities that had befallen the kingdom to the true cause, namely, apostasy from God. The country had been laid waste by successive wars of invasion, and its resources drained. Many families mourned members of their household still suffering the miseries of foreign captivity; all their former prosperity and glory had fled; and to what was this painful and humiliating state of affairs to be traced, but to the manifest judgment of God upon the kingdom for its sins?
2 Chronicles 29:10
ch2 29:10Now it is in mine heart to make a covenant with the Lord God--Convinced of the sin and bitter fruits of idolatry, Hezekiah intended to reverse the policy of his father, and to restore, in all its ancient purity and glory, the worship of the true God. His commencement of this resolution at the beginning of his reign attests his sincere piety. It also proves the strength of his conviction that righteousness exalteth a nation; for, instead of waiting till his throne was consolidated, he devised measures of national reformation at the beginning of his reign and vigorously faced all the difficulties which, in such a course, he had to encounter, after the people's habits had so long been moulded to idolatry. His intentions were first disclosed to this meeting of the priests and Levites--for the agency of these officials was to be employed in carrying them into effect.
2 Chronicles 29:12
ch2 29:12THE HOUSE OF GOD CLEANSED. (2Ch. 29:12-36)
Then the Levites arose--Fourteen chiefs undertook the duty of collecting and preparing their brethren for the important work of cleansing the Lord's house. Beginning with the outer courts--that of the priests and that of the people--the cleansing of these occupied eight days, after which they set themselves to purify the interior; but as the Levites were not allowed to enter within the walls of the temple, the priest brought all the sweepings out to the porch, where they were received by the Levites and thrown into the brook Kedron. This took eight days more. At the end of this period they repaired to the palace and announced that not only had the whole of the sacred edifice, within and without, undergone a thorough purification, but all the vessels which the late king had taken away and applied to a common use in his palace, had been restored, "and sanctified."
2 Chronicles 29:20
ch2 29:20Then Hezekiah the king rose early, and gathered the rulers of the city--His anxiety to enter upon the expiatory service with all possible despatch, now that the temple had been properly prepared for it, prevented his summoning all the representatives of Israel. The requisite number of victims having been provided, and the officers of the temple having sanctified themselves according to the directions of the law, the priests were appointed to offer sacrifices of atonement successively, for "the kingdom," that is, for the sins of the king and his predecessors; for "the sanctuary," that is, for the sins of the priests themselves and for the desecration of the temple; "and for Judah," that is, for the people who, by their voluntary consent, were involved in the guilt of the national apostasy. Animals of the kinds used in sacrifice were offered by sevens, that number indicating completeness. The Levites were ordered to praise God with musical instruments, which, although not originally used in the tabernacle, had been enlisted in the service of divine worship by David on the advice of the prophets Gad and Nathan, as well calculated to animate the devotions of the people. At the close of the special services of the occasion, namely, the offering of atonement sacrifices, the king and all civic rulers who were present joined in the worship. A grand anthem was sung (Ch2 29:30) by the choir, consisting of some of the psalms of David and Asaph, and a great number of thank offerings, praise offerings, and freewill burnt offerings were presented at the invitation of the king.
2 Chronicles 29:31
ch2 29:31Hezekiah . . . said, Now ye have consecrated yourselves unto the Lord, come near--This address was made to the priests as being now, by the sacrifice of the expiation offerings, anew consecrated to the service of God and qualified to resume the functions of their sacred office (Exo 28:41; Exo 29:32).
the congregation brought in--that is, the body of civic rulers present.
2 Chronicles 29:34
ch2 29:34the priests were too few, . . . wherefore their brethren the Levites did help them--The skins of beasts intended as peace offerings might be taken off by the officers, because, in such cases, the carcass was not wholly laid upon the altar; but animals meant for burnt offerings which were wholly consumed by fire could be flayed by the priests alone, not even the Levites being allowed to touch them, except in cases of unavoidable necessity (Ch2 35:11). The duty being assigned by the law to the priests (Lev 1:6), was construed by consuetudinary practice as an exclusion of all others not connected with the Aaronic family.
for the Levites were more upright in heart to sanctify themselves than the priests--that is, displayed greater alacrity than the priests. This service was hastened by the irrepressible solicitude of the king. Whether it was that many of the priests, being absent in the country, had not arrived in time--whether from the long interruption of the public duties, some of them had relaxed in their wonted attentions to personal cleanliness, and had many preparations to make--or whether from some having participated in the idolatrous services introduced by Ahaz, they were backward in repairing to the temple--a reflection does seem to be cast upon their order as dilatory and not universally ready for duty (compare Ch2 30:15). Thus was the newly consecrated temple reopened to the no small joy of the pious king and all the people.