(Mishnah): There are two primary oaths of Bituy (that one will or will not do something). There are four in all;

There are two primary Yedi'os (awarenesses) of Tum'ah. There are four in all;

There are two primary forms of Yetzi'ah (taking things out) on Shabbos. There are four in all;

There are two primary appearances of Tzara'as. There are four in all.

(Continuation of Mishnah - R. Yehudah): If one knew of the Tum'ah, and later forgot (and entered the Mikdash or ate Kodshim), and later remembered that he was Tamei, he brings an Oleh v'Yored Korban (i.e. a rich person brings an animal, a poor person brings birds, and a very poor person brings a flour offering);

If he knew of the Tum'ah, and forgot (and entered the Mikdash or ate Kodshim), and did not remember before Yom Kipur, the goat (whose blood is) offered inside (the Kodesh ha'Kodoshim on Yom Kipur) and Yom Kipur itself protect him from punishment;

When he remembers, he must bring an Oleh v'Yored;

If he never knew of the Tum'ah (and entered the Mikdash or ate Kodshim), and later was told that he had was Tamei, the goat (whose blood is) offered outside (the Heichal) and Yom Kipur itself atone for him;

(When the Torah commands about the outer goat on Yom Kipur, it says "Milvad Chatas ha'Kipurim" to teach that it atones for the same things as the inner goat.

Just like the inner goat atones for Tum'ah that was known at some time, also the outer goat.

The goats of the Mo'adim and Rosh Chodesh atone for Tum'ah that was never known.

R. Shimon says, the goats of the Mo'adim atone for this, but not those of Rosh Chodesh;

The goats of Rosh Chodesh atone for a Tahor person who ate Tamei Kodshim.

R. Meir says, all the goats atone for the same things, i.e. Tum'ah of the Mikdash or Kodshim.

(Recap): R. Shimon says, the goats of Rosh Chodesh atone for a Tahor person who ate Tamei Kodshim;

The goats of the Mo'adim atone for Tum'ah that was never known;

The outer goat of Yom Kipur atones for Tum'ah that was known only after he transgressed.

Question (Rabanan): If a goat designated for one of these three atonements was lost, and it was found after a substitute was offered, may the found goat be used for another of the three atonements?

Answer (R. Shimon): Yes.

Question (Rabanan): If it was originally designated for one atonement, how can it atone for something else?!

Answer (R. Shimon): They all atone for (transgressions involving) Tum'ah in the Mikdash or with Kodshim. This is essentially what it was designated for!

(R. Shimon ben Yehudah citing R. Shimon): The goats of Rosh Chodesh atone for a Tahor person who ate Tamei Kodshim;

The goats of the Mo'adim atone for this, and also for Tum'ah that was never known;

The outer goat of Yom Kipur atones for both of these, and also for Tum'ah that was known only after he transgressed.

Question (Rabanan): If a goat designated for one of these three atonements was lost, and it was found after a substitute was offered, may the found goat be used for another of the three atonements?

Answer (R. Shimon): Yes.

Question (Rabanan): Indeed, the outer goat of Yom Kipur may be used on Rosh Chodesh, since it was designated to atone for more;

However, how can a goat designated for Rosh Chodesh be used on Yom Kipur? It was originally designated to atone for less!

Answer (R. Shimon): They all atone for Tum'ah of the Mikdash or Kodshim. This is essentially what it was designated for!

The inner goat and Yom Kipur atone for intentional Tum'ah in the Mikdash or with Kodshim;

The goat sent to Azazel (on Yom Kipur) atones for all other transgressions, light or severe, intentional or unintentional, whether or not the person knows he sinned, Lav or Aseh, even what is punishable by Kares or death;

It atones for Yisraelim, Kohanim and a Kohen Gadol anointed (with Shemen ha'Mishchah, special oil from the days of Moshe) alike;

The difference between them is that the bull (of Yom Kipur) atones for the Kohanim for Tum'ah in the Mikdash or with Kodshim (the Gemara will address the contradiction between this and the previous clause);

R. Shimon says, just like blood of the inner goat atones for Yisrael, so the blood of the bull atones for Kohanim;

Just like the confession said over the goat sent to Azazel atones for Yisrael, so the confession said over the bull atones for Kohanim.