And the king went up into the house of the Lord, and all the men of Judah and all the inhabitants of Jerusalem with him, and the priests, and the prophets, and all the people, both small and great: and he read in their ears all the words of the book of the covenant which was found in the house of the Lord. (2 Kings 23:2)
As far as possible, all the men of the nation were to be brought together to Jerusalem to hear the message of God. The solemn conclave would include men of all classes and occupations, particularly the priests and prophets—the religious leaders of the people who might be most influential in helping to bring about the desired reform.