On Shmini Atzeres, in the diaspora, the Haftora we read, tells us how the First Beis Hamikdash was dedicated by Shlomo Hamelech (king Solomon). It was a two week festival which included Yom Kippur (that year, they didn't fast on Yom Kippur, Shlomo Hamelech, being a prophet, commanded them not to. A prophet cannot cancel a mitzvah, but can suspend a mitzvah as a one time occasion.)
The Haftora tells us the beautiful blessing that Shlomo Hamelech gave the Jewish people. Thousands of sacrifices were brought, the altar wasn't big enough, so Shlomo Hamelech consecrated the entire area in front of the Heichal (the area around the altar) to offer the sacrifices.
Why do we read this Haftora on Shmini Atzeres?
One reason, is that the Haftora says, "On the eighth day he sent the nation," Shmini Atzeres is the eighth day.
Another reason, the Zohar tells us, that every day of Sukkos, we are visited by the Ushpizin, special spiritual guests. The first day Avraham, then Yitzchak, Yaakov, Moshe, Aharon, Yosef and David. It would follow that on Shmini Atzeres, the Ushpizin would be Shlomo, therefore we read of his crowning achievement, the completion of the Beis Hamikdash.
The verse continues, "they blessed the king and went to their tents happy and good-hearted over all the good Hashem did for His servant David and his nation Yisrael." Shmini Atzeres is the end of the holidays, it is when we take all the blessings from all the holidays and bring it home. To take the energy from the holidays and apply it to the year. This is yet another message in the Haftora, and perhaps the most important and practical ideas found there in. After you build the Beis Hamikdash, take it home with you, allow the holiness to be part of your daily lives.
May Hashem give us the ultimate blessing, the third and final Beis Hamikdash, and may we stand together with all the Ushpizin to dedicate it. May it happen soon.
Dedicated to the memory of Rabbi Mendel Brickman, a friend who was a source of strength and inspiration to me. He was regal like a king and holy like a Beis Hamikdash. May his family be consoled, and may his memory go on. He will be missed by all.