2 Chronicles 30:3 Commentary - English Annotations on the Holy Bible by Matthew Poole
They could not keep it at that time, which God had appointed for it, Exo 12:6; one reason whereof was evident in itself, because the temple was not then purified and prepared; to which he adds two other reasons.
The priests had not sanctified themselves sufficiently, to wit, in such manner and degree as was fit, nor in such numbers as were necessary for the flaying and offering of so many thousands of paschal offerings, as appears, because they were not sufficient for those offerings, which were comparatively few, 2Ch 29:32-34.
Neither had the people gathered themselves together to Jerusalem; as they used and ought to do at that time from all places; which now they could not do, because neither the thing was agreed upon, nor the people summoned thither, till the proper time was past.
Consult other comments:
2 Chronicles 30:3 - Albert Barnes' Notes on the Bible
2 Chronicles 30:3 - Joseph Benson’s Commentary on the Old and New Testaments
2 Chronicles 30:3 - The Cambridge Bible for Schools and Colleges
2 Chronicles 30:3 - Companion Bible Notes, Appendices and Graphics
2 Chronicles 30:3 - Ellicott's Commentary for English Readers (Old and New Testaments)
2 Chronicles 30:3 - John Gill's Exposition of the Entire Bible
2 Chronicles 30:3 - English Annotations on the Holy Bible by Matthew Poole
2 Chronicles 30:3 - John Trapp's Complete Commentary (Old and New Testaments)
English Annotations on the Holy Bible by Matthew Poole

Matthew Poole (1624–1679) wrote English Annotations on the Holy Bible, completing the chapters as far as Isaiah 58 before his death in 1679. The rest of the Annotations were completed by friends and colleagues among his Nonconformist brethren. The first printing of the completed edition was in 1685, 2 volumes folio, followed by editions in 1688, 1696 (with valuable chapter outlines added by the editors, Samuel Clark and Edward Veale), and the 4th and definitive edition in 1700, the basis of all others.