We're told, that during the entire seven day investiture of The Kohen Gadol (High Priest) and the kohanim, Moses acted in the role of the High Priest but never donned the special garments of that office, to preserve the honor for Aaron, his brother.
As a sidebar, there is prophetic link to the installment of the Aaron, and the future builder of the Beit HaMikdash, King Solomon:
Leviticus 8:9, states a kind of crown is placed on the head of Aaron, as the High Priest: "And he set the headdress on [Aaron's ]head; and on the headdress, in front, he put the gold crown, the holy diadem—as HaShem had commanded Moses" Those words happen to be the 2924th verse in the Torah and King Solomon was crowned as King in the year 2924 from Adam, on the Hebrew calendar.
The laws for the proper slaughtering the daily offerings are found here in Parashat Tzav but it represents a challenge to modern Jews and non-Jews alike. We may be repulsed by the idea of an innocent animal being ritually slaughtered then eaten or consumed by fire. We can reject these concepts or we can accept the korbanot because HaShem has a unique purpose for every creation. For example, specific animals were made to be eaten, especially after the Mabbul (Flood of Noach).
Consider how HaShem made provision for the animal offerings, after the Flood when He commands Noach to bring in, not just all manner of infant creatures paired up as male and females, He specifically commanded that Noach bring:
“Of every pure animal you shall take seven pairs, males and their mates, and of every animal that is not pure, two, a male and its mate; - Genesis 7:2
If post-flood humans were allowed to eat animals, why would our Creator give such a specific directive? Rashi relates that, HaShem commanded those seven types of animals to be brought on board so that they would more available for the korbanot.
Since the Creator endorsed the use of animal as the korbanot, who are we to question Him?
If the reader objects to the slaughtering of animals for korbanot on the grounds that it it is cruel, you should be aware that the process as practiced by a trained shochet causes no pain. If, for some reason, the animal does feel pain, that animal is unfit as an offering.
Recall one of the lessons from The Akeidah, when Avraham attempted to offer Isaac, was to demonstrate that human sacrifice is completely unacceptable. The korbanot draws the line separating man and animal. By now, it should be obvious that our lives have far more value in the eyes of the Creator. Forgetting this leads to viewing cows, trees, even gold, more valuable than human lives.
Pesach is fast approaching, celebrating Israel's freedom from a nation that deified animals. Yet, Israel (painlessly) slaughtered one of Egypt's "gods", dined on it and stained their doorposts with its blood, to demonstrate that Israel only worships the One True Creator.
Why even study the laws of korbanot when offerings cannot be brought without the Temple?
Because, embedded in these sacred commandments, are eternal principles. According to the Baal Haturim, one who studies these teachings is “counted as if he brought an offering himself .”
Another command given in Parashat Tzav is to keep a Perpetual Fire burning on the altar. On a deeper level it's the Creator’s call for the Jewish People to fill their days with service to God and humanity, fueling such service with enthusiasm—so that the holy never becomes the mundane. As Rav Kook taught: “Daily contemplation of G-d’s wonders and renewed study of His Torah rejuvenates the soul. This renewal energizes the soul, giving strength to new deeds and aspirations, and awakening a new spirit of life from the soul’s inner fire."