1) THE SOURCE FOR "SEMICHAH" AND "SHIRAYIM" FOR THE PAR YOM HA'KIPURIM
QUESTION: The Gemara explains that according to Rebbi Yehudah, the words "Ken Ye'aseh" (Vayikra 4:20) teach that the Par Yom ha'Kipurim requires Semichah and Shefichas Shirayim, like the Par He'elem Davar. The Gemara asks why the words "Ken Ye'aseh" are needed to teach this, when it can be learned from "l'Far" (ibid.), which includes the Par Yom ha'Kipurim in the laws of Par He'elem Davar (39b). The Gemara answers that one might have thought that this inclusion applies only to a part of the Avodah on which the validity of the Korban to depends, but to Semichah and Shefichas Shirayim. This is why the words "Ken Ye'aseh" are necessary.
What is the basis of the Gemara's logic? Why should "l'Far" include only an Avodah on which the validity of the Korban depends?
(a) RASHI (DH Salka) writes that since the verse says, "v'Chiper," it is clear that the verse refers only to parts of the Avodah on which the atonement depends.
(b) TOSFOS (DH l'Semichah) notes that this Tana learns from the inclusion of the Par Yom ha'Kipurim that the Yoseres and Kelayos (diaphragm and kidneys) are burned on the Mizbe'ach, even though this Avodah is not absolutely necessary for the Korban to be valid.
Accordingly, the reason why Semichah and Shefichas Shirayim should not be included in the word "l'Far" is that the word "v'Asah" in this verse implies an important Avodah. Burning the limbs on the Mizbe'ach is considered an important Avodah, while Semichah and Shefichas Shirayim are not considered important enough to be included in the verse.
Tosfos supports the fact that Shefichas Shirayim is not considered an important Avodah from the Gemara later (111a). The Gemara there states that while the burning of the limbs is considered part of the beginning of a Korban's Avodah, Shefichas Shirayim is considered part of the end of a Korban's Avodah.
The TAHARAS HA'KODESH explains that Tosfos does not learn like Rashi because he understands that the word "v'Chiper" refers to the Korban itself, while "v'Asah" refers to the Avodos of the Korban. (Mordechai Zvi Dicker, Y. MONTROSE)
2) WHY COMPARE "PAR YOM HA'KIPURIM" TO "PAR KOHEN MOSHIACH?"
QUESTION: The Torah states regarding the Par He'elem Davar, "v'Asah la'Par Ka'asher Asah l'Far ha'Chatas" -- "And he shall do with the bull as he did with the bull of the Chatas" (Vayikra 4:20). The Beraisa (39a) states that the first word "la'Par" includes the Par Yom ha'Kipurim, and the second "l'Far" includes the Par Kohen Mashi'ach. The word "ha'Chatas" includes a Chatas brought by the people for a communal transgression of the sin of idolatry. The verse teaches that all of their Zerikos must be done in order for the Korban to be valid.
The Gemara here teaches that three laws are derived from the inclusion of the Par Yom ha'Kipurim in the verse: the laws of "Es b'Dam v'Tevilah." RASHI (40a, DH Ela l'Es) explains that the Par Yom ha'Kipurim is compared to the Par Kohen Mashi'ach, which is also included in the verse of Par He'elem Davar, as mentioned above. With regard to the Par Kohen Mashi'ach the verse says, "And he will dip his finger in the blood." This verse is the source for the three laws of "Es b'Dam v'Tevilah" (as the Gemara here explains at length). The comparison teaches that the Par Yom ha'Kipurim has the same three laws of "Es b'Dam v'Tevilah."
Why does the Gemara assume that the Par Yom ha'Kipurim should be compared to the Par Kohen Mashi'ach? The fact that both are included in the verse of the Par He'elem Davar does not necessitate that their laws be shared.
(a) RASHI (40a, DH Ela l'Es) answers this question by clarifying the Gemara's derivations from the verse. Once the Gemara teaches that the word "la'Par" in the verse includes the Par Yom ha'Kipurim, and the second "l'Far" includes the Par Kohen Mashi'ach, it is necessary to go back and read the verse accordingly. Besides including these Korbanos in the laws of Par He'elem Davar, the verse now reads that whatever is done to the Par Kohen Mashi'ach should be done to the Par Yom ha'Kipurim. Hence, the Par Yom ha'Kipurim is compared to the Par Kohen Mashi'ach.
TOSFOS (40a, DH Lo Nitzrechah Ela l'Es) has difficulty with Rashi's explanation. The Gemara also derives these laws for the communal Chatas brought for the sin of idolatry. How does Rashi know that the Chatas for idolatry is compared to the Par Kohen Mashi'ach? RABEINU TAM concludes that while some of the laws of the Par Kohen Mashi'ach are considered as though they are stated with regard to the Par He'elem Davar as well (and it is logical to compare the Chatas of idolatry to the Par He'elem Davar, based on the teaching of the Gemara earlier on 39b), how are the other laws, such as "b'Dam v'Tevilah," derived from the Par Kohen Mashi'ach? There is no reason to compare the Chatas of idolatry to the Par Kohen Mashi'ach! (See TAHARAS HA'KODESH, who defends the explanation of Rashi.)
(b) RABEINU TAM explains that the laws of "Es b'Dam v'Tevilah" in fact are stated with regard to the Par He'elem Davar as well, in the verse, "And he will dip his finger from the blood" (Vayikra 4:17). Accordingly, the comparison is actually from the Par Yom ha'Kipurim to the Par He'elem Davar (based on the teaching on 39b). The Gemara merely quotes the similar verse which is stated with regard to the Kohen Mashi'ach (from Vayikra 4:6) because this is the first similar verse stated in the Parshah of these types of Korbanos. However, the fact that a number of Korbanos are included in the verse of Par He'elem Davar is not a reason to compare those included Korbanos to each other. (Mordechai Zvi Dicker, Y. MONTROSE)