Here’s an interesting tidbit about the Temple service (in the Beit HaMikdash) on Yom Kippur: The High Priest had to perform almost every part of the service himself. Ordinarily any Kohain (priest) could be assigned to do almost any Temple service task. But not on Yom Kippur! On this holiest day of the year, the High Priest had to do all aspects of the service, even things that weren’t directly related to Yom Kippur.
For example there’s the Korban Tamid, the daily morning and afternoon sacrifice. It is usually done by any Kohain. But on Yom Kippur it was offered by the High Priest only. Same when it came to preparing and kindling the Menorah. Slaughtering the sacrifices, sprinkling their blood on the altar. The daily burning of incense on the Inner/Golden Altar (near the Menorah, not in the Holy of Holies). All by the Kohain Gadol, the High Priest. He could get help of course, but for the most part it was a one-man show. He did everything.
What’s the point of wearing down the Kohain Gadol like this? What’s wrong with other Kohanim helping out by doing some of the ordinary everyday Temple tasks? What did he do that was so different? Why was this so important?
Rebbe spoke about this concept a lot when I was a yeshiva student. It’s a message that the Alter Rebbe speaks of at the end of Tanya 25: The Ultimate into the Everyday.
It’s not enough for the high priest to do high priest things and the regular kohain to do just regular kohain stuff. The ideal, the Yom Kippur service, is for the high priest wavelength and higher level spirituality to suffuse and animate and be part of everything normal and regular, too.
But first the Alter Rebbe and more so the Rebbe took this far beyond Yom Kippur. Rebbe was eager for this to be a new Jewish normal! Rebbe pushed and encouraged for the Jewish essence and core to be expressed into our normal regular everyday lives.