In today’s Chumash, Hashem gives instructions of how the Kohen Gadol should do his avodah on Yom Kippur to bring forgiveness to the Yidden.

After Nadav and Avihu passed away, Hashem told Moshe to teach Aharon how to act in the Mishkan.

Even if he feels that he wants to be close to Hashem, Aharon is not allowed to go into the Kodesh HaKodoshim whenever he wants to, so that he shouldn’t make the same mistake as his sons did. Inside the Kodesh Hakodoshim, Hashem’s Shechinah rests, on the Aron, and it is asur to go inside unless it is the proper time.

Aharon Hakohen (and every other Kohen Gadol) is only allowed to come into the Kodesh Hakodoshim when he brings the Ketores on Yom Kippur.

Even then, he needs to follow all of the steps of the Yom Kippur Avodah:

He will not be wearing the special clothes of the Kohen Gadol — instead he wears four pieces of white linen clothing, because gold can remind Hashem of the Cheit Ha’Egel. These clothes are holy, and he needs to go to the mikvah every time before he puts them on — it’s not enough that he went to the mikvah in the morning.

First, wearing the special clothes of the Kohen Gadol, he does the regular morning Avodah — bringing the Korban Tomid and ketores, cleaning out the menorah, and bringing his daily Korban Mincha. Then he puts on the Yom Kippur clothing to do the special Yom Kippur Avodah.

The Kohen Gadol first says vidui over a korban that he will bring to Hashem to be forgiven for any aveiros connected to the Mishkan or korbanos.

Then he makes a goral: The Kohen Gadol stands between two goats. He picks two lots from a container, one with his right hand, and one with his left. The side with the lot that says “For Hashem” will be brought as a korban, and the side with the lot that says “For Azazel” will later be sent away to be killed in the desert.

Once the goral is decided, the Kohen Gadol shechts his korban, saving the blood for the next part of the Avodah.

Now that he has asked Hashem to forgive him for his own aveiros, the Kohen Gadol brings the ketores inside of the Kodesh Hakodoshim. Nobody is allowed to be even inside of the Kodesh at this time.

The Kohen Gadol leaves the burning ketores on the floor near the Aron, and goes to get the blood of his korban. He comes back and sprinkles the blood of his korban on the side of the Aron’s cover — one time upwards, and seven times downward.

He then shechts the korban for the Yidden’s aveiros, and brings its blood into the Kodesh Hakodoshim to be sprinkled there too. This will bring Hashem to forgive the Yidden for aveiros they did by eating korbanos or coming into the Mishkan when they weren’t tahor — by mistake or on purpose.

To forgive the Yidden in case they made the Menorah, Shulchan, or Mizbeiach Haketores tomei, the Kohen Gadol then sprinkles blood on the Paroches.

Now we learn how the Kohen Gadol is mechaper for any mistakes with the kedusha of the Mizbeiach Hapnimi, where the ketores was brought. The Kohen Gadol sprinkles the Mizbeiach Hapnimi with the same mixture of blood. This brings Hashem to forgive the Yidden in case the Mizbeiach became tomei by touching something tomei, or if the ketores had become tomei.

Then the Kohen Gadol goes out of the Kodesh and the person chosen the day before brings the goat for Azazel. The Kohen Gadol says vidui, asking forgiveness for all of the aveiros of the Yidden, leaning his hands on the goat’s head. Then he sends the goat to the desert with a kohen, to push the animal off the Azazel cliff. This takes away the aveiros of the Yidden.

The Kohen Gadol takes the fat of the korbanos to be burned on the Mizbeiach. Then he goes to the Mikvah to change back into the clothes of the Kohen Gadol that he wears all year (the Bigdei Zahav). He brings a Korban Olah for himself and for the Yidden. Then he brings seven sheep for the Korban Musaf of Yom Kippur.