To keep other seven days - This was a voluntary addition to the requirements of the Law - the fruit and sign of the abounding zeal which characterized the time. Hezekiah and the princes probably proposed it to the people, and presented them with sacrificial animals.
Related Commentaries of 2 Chronicles 30:23
2 Chronicles 30:23
23 And the whole assembly took counsel to keep other seven days: and they kept other seven days with gladness.