"And the Kohanim and the people standing in the Courtyard when they would hear the glorious, awesome Name, the Ineffable one, emanating from the Kohen Gadols mouth, in holiness and purity, they would kneel and prostrate themselves, give thanks and say, Blessed is the Name of His glorious kingdom for all eternity."
In the middle of the Mussaf service, we recite the Kohen Gadols Seder Avodah, order of service. This recalls in a somewhat detailed fashion, the service as performed by the Kohen Gadol in the Holy Temple during the day of Yom Kippur. The Kohen Gadols service was both physically and mentally exhausting as it required both physical dexterity (while fasting and having no sleep) and total mental concentration.
The eyes of all Israel were raised towards the Kohen Gadols order of service, which began toward the break of dawn. On his success, the atonement of all Israel was dependent. When the Kohen Gadols service was performed properly, Israels total forgiveness was made manifest for all eyes to see. The Kohen Gadol tied a cord of red painted wool between the horns of the scapegoat. Another such cord had been tied by him around the neck of the goat reserved for the sin-offering, so that it might not be commingled with the other goats held for the remaining offering of the day. The cord used for the scapegoat was later divided in two. One remaining between the scapegoats horns, and the other half hung upon the opening of the hallway leading to the Sanctuary, so that all might see it.
In years when the avodah was accepted by G-d and atonement was granted Israel, both parts of the cord turned white like snow, in accord with the verse, "If your sins should be like red thread, they will turn like snow. (Isaiah Chapter 1) Thereupon all eyes saw G-ds forgiveness and the hearts of the people rejoiced.
Today, 3 times during the Seder Avodah we prostrate ourselves on the ground as they did in the days of the temple. (By the way, the paper towels given out are not to keep your knees from getting dirty, but rather involve a halachic issue of keeping a separation between you and the ground.) We try to relive and experience, as much as possible, the feelings of inspiration and closeness to G-d that existed in Temple.
On the holiest day of the year, in the holiest place on earth, the holiest man on the planet, uttered the holiest word in the Universe .. Such was the task of the Kohen Gadol on Yom Kippur.
May we all see the rebuilding of Jerusalem today, here in our times.
Torah Readings On Yom Kippur