Dora Bas Rivka Silver O'H
You Are Cordially Invited…
Chizkiyahu sent letters throughout both Judah and the northern kingdom inviting the people to come celebrate Passover at the Temple. They decided to make the year a "leap year" (with the second month of Adar) so Passover fell a month later, giving the kohanim and the people adequate time to prepare. (See Talmud Sanhedrin 12a-b for a discussion of this matter.)
Messengers traveled the width and breadth of the land conveying the invitation. Chizkiyahu encouraged the people to serve G-d enthusiastically and perhaps He would return the Tribes that had already been exiled by Assyria. (The dispersion of the Ten Tribes had begun by this point, but it happened in waves and was far from finished.) For the most part, the Tribes of the northern kingdom laughed at the invitation, although some individuals did take it seriously. These individuals joined Judah for Passover in Jerusalem.
The people who gathered in Jerusalem were filled with religious zeal and they destroyed the altars to idols that were there. The kohanim and Leviim were ashamed that they didn't prepare themselves in time, necessitating the insertion of the disputed "leap month," but they purified themselves and performed the service. Many people, notably those from the north, had not been purified and ate the Passover offering in a state of ritual uncleanliness (which is prohibited). Chizkiyahu prayed for them and asked G-d's forgiveness; they may not be perfect, Chizkiyahu said, but at least they're trying. G-d heeded this prayer and pardoned the people.
The week of Passover was celebrated with great joy, with daily songs of praise to G-d. Chizkiyahu inspired the Levites on religious matters and they offered sacrifices of thanks all week long. When the week of Passover concluded, the people decided to stay another week, to celebrate the renewal of the Temple, with many more sacrifices offered in great joy. This was the most festive occasion in Jerusalem since Solomon first opened the Temple some three centuries earlier. The priests and Levites blessed the people and their words were received by G-d in Heaven.