Carl Friedrich Keil and Franz Delitzsch Old Testament Commentary
The celebration of the passover. - Ch2 30:13. The assembly of the people at Jerusalem to celebrate the feast became a great congregation.
Ch2 30:14
Before the slaying of the passover, in order to purify and sanctify the city for the feast, they removed the (illegal) altars and places for offering incense which had been erected under Ahaz (Ch2 28:24), and threw them into the Kidron (Ch2 29:16). מקטּרות is here a substantive: places for incense-offerings (cf. Ew. 160, e), and denotes altars intended for the offering of the קטרת.
Ch2 30:15
When they slaughtered the passover on the 14th, the Levites and priests also were ashamed, i.e., had sanctified themselves under the influence of a feeling of shame, and offered the sacrifice in the house of the Lord; i.e., they performed the sacrificial functions incumbent upon them at the passover in the temple, as is stated more in detail in Ch2 30:16. The clause וגו והכּהנים is a circumstantial clause, and the statement points back to Ch2 30:3. The mention of Levites along with the priests here is worthy of remark, since in Ch2 29:34 it is said that at the celebration of the dedication of the temple the Levites had sanctified themselves more zealously than the priests. But these two statements do not contradict each other. In Ch2 29:34 it is the Levites and priests then present in or dwelling in Jerusalem who are spoken of; here, on the contrary, it is the priests and the Levites of the whole kingdom of Judah. Even though, at the former period, the Levites were more zealous in sanctifying themselves for the dedication of the temple, yet there must certainly have been many Levites in Judah, who, like many of the priests, did not immediately purify themselves from their defilement by the worship in the high places, and were only impelled and driven to sanctify themselves for the service of the Lord by the Zeal of the people who had come to Jerusalem to hold the passover.
Ch2 30:16-17
Standing in their place, according to their right, i.e., according to the prescribed arrangement (see on Ch1 6:17), the priests sprinkled the blood (of the paschal lambs) from the hand of the Levites, they handing it to them. This was not the rule: in the case of the paschal lamb, the father of the family who slew the lamb had to hand the blood to the priest, that it might be sprinkled upon the altar; here the Levites did it for the reasons given in Ch2 30:17. Because many in the assembly had not sanctified themselves, the Levites presided over the slaying of the paschal lambs for every one who was unclean, to sanctify (the lambs) to the Lord (see also on Ch2 35:6, Ch2 35:11). רבּת, stat. constr. before the noun with a preposition, stands as neuter substantively: there was a multitude in the assembly who...רבּת, in Ch2 30:18 is to be taken in a similar manner, not as an adverb (Berth.). וגו מאפרים רבּת is in apposition to העם מרבּית, a multitude of people, viz.: Many of Ephraim ... had not purified themselves, but ate the passover in an illegal fashion, not according to the precept (cf. Num 9:6). This clause explains how it happened that the Levites presided at the slaying of the passover for those who had not sanctified themselves, i.e., they caught the blood and gave it to the priests. Had this been done by persons levitically unclean, the expiatory sacrificial blood would have been defiled. The eating of the paschal lamb or the participation in the passover meal was indeed allowed only to the clean; but yet it was not so holy an act, i.e., did not bring the people into such immediate contact with God, who was present at His altar, that those who were not clean might not, under some circumstances, be admitted to it. Here it was allowed, for Hezekiah had prayed for them that God might forgive the transgression of the law.
Ch2 30:18-19
John Gill Bible Commentary
For Hezekiah king of Judah did give to the congregation one thousand bullocks, and seven thousand sheep,.... He separated them, as Kimchi interprets it, from his own herds and flocks; or out of his own substance, at his own expense purchased them; or lifted them up, as the word signifies, as heave offerings to the Lord; and gave them to the people for thank offerings to feast upon:
and the princes gave to the congregation one thousand bullocks, and ten thousand sheep: for the same purposes, following the king's example:
and a great number of priests sanctified themselves; besides those who had before, that they might be fit to offer this great number of sacrifices.