They proceeded to remove the altars in Jerusalem and to take away the incense altars and throw them into the Kidron Valley.
The time appointed for the passover having arrived, a very great congregation came together upon the occasion, Ch2 30:13. Now here we have, I. The preparation they made for the passover, and good preparation it was: They took away all the idolatrous altars that were found, not only in the temple, but in Jerusalem, Ch2 30:14. Before they kept the feast, they cast out this old leaven.
Commenting on 2 Chronicles 30:13-20
Then they killed the passover on the fourteenth day of the second month,.... For though they could not keep it in the month in which it should have been kept, for the reasons before given, yet they kept it on the day of the month in which it was observed: and the priests and the Levites were ashamed; of their negligence and backwardness to service...
THE ASSEMBLY DESTROYS THE ALTARS OF IDOLATRY. (Ch2 30:13-27) they arose and took away the altars that were in Jerusalem--As a necessary preparation for the right observance of the approaching solemnity, the removal of the altars, which Ahaz had erected in the city, was resolved upon (Ch2 28:24); for, as the people of God, the Hebrews were bound to extirpate all traces of idolatry; and...