Today is Yom Kippur (day of atonement) it began yesterday at sunset. I wrote a pretty lengthy post about this holiday last year. My Yom Kippur post from last year is the most popular post on this blog in terms of page views.
In the Bible the holiday is discussed in Leviticus 16, Leviticus 23, and Numbers 29. These links will also show you the verses in Hebrew. I think the book of Jonah is traditionally read on this holiday. In the book of Jonah the people of Nineveh are given the chance to repent of their sins. Yom Kippur is about forgiveness and new beginnings.
I wanted to discuss what this holiday looked like in the times of the Temple and why this is the holiest day of the year on the Jewish calendar. Temples in the ancient world were different from synagogues and churches of today. In the ancient world temples were seen as the dwelling place of the god on earth. Since the building was holy only priests were allowed to enter. The sacrifices actually took place on an altar outside the Temple. Only the priests were allowed inside the Temple building itself. The Temple itself has three sections the Ulam (porch), the hechal(place of the altars of incense and tables of show bread), and the Dvir (Holy of Holies). The Holy of Holies was the place the ark of the covenant was kept. Only the high priest could enter the Holy of Holies and only on one day of the year...Yom Kippur. There was a fairly complex ritual involved for the high priest that is discussed in this article scroll down a bit to find it. This was the day that the name of the Lord was pronounced three times by the high priest. I believe this was the only time of year that the name of the Lord was pronounced and only by the High priest. Today no one is sure how to pronounce the name of the Lord since only the High priest knew. I think the knowledge was lost when Hadrian rebuilt Jerusalem and forbid the Jews from entering there was no Temple and no High priest and the knowledge was lost.
You can read about the building of the first Temple by Solomon in 1 Kings 6. And here is a picture of a model of the Second Temple built by King Herod that is on display at the Israel museum.