1) THE REQUIREMENT TO BUY THE TWO GOATS AT ONE TIME
QUESTION: The Mishnah states that the two Se'irim of Yom Kippur must be equal in appearance, height, and value, and they must be purchased at one time ("Lekichasan k'Achas"). The Gemara derives these requirements from the threefold repetition of the word "Shnei Se'irim" ("two goats") in Parshas Acharei Mos, which teaches that the two Se'irim must be identical in three ways.
However, the Mishnah teaches four Halachos with regard to the two Se'irim, but there are only three sources in the verses. What is the source for the fourth Halachah, that the two Se'irim must be purchased at one time?
(a) The TOSFOS YESHANIM and RABEINU ELYAKIM have a different text in the Gemara. According to their text, the Gemara derives from one word "Shnei" both that the two Se'irim must be equal in appearance and that they must be equal in height. This word teaches that they must look the same, which includes the requirement that they must be of the same height. (The Mishnah nevertheless expresses that they must be the same height in order that one not mistakenly think that the second Sa'ir may be a miniature clone of the first.) Accordingly, two words "Shnei" are left, one to teach that the Se'irim must be equal in value and one to teach that they must be purchased at the same time. (The first verse teaches a Halachah about their physical appearance. The second verse teaches a Halachah about their value. The third verse teaches a Halachah about when they are purchased.)
(b) The TOSFOS YESHANIM suggests further that perhaps the Halachah of "Lekichasan k'Achas" is not derived from the word "Shnei" alone, but from the fact that the word "Shnei" is written next to the word "Yikach" ("buy"). The Halachah that the Se'irim must be purchased at one time is derived from the proximity of the words.
2) THE SOURCE FOR THE REQUIREMENT THAT TWO ANIMALS LOOK ALIKE
QUESTION: The Gemara records a series of Derashos about different types of Korbanos which are brought in pairs. In each case, the word "Shnei" teaches that the two animals must be identical. The Gemara says that although this Derashah applies to the two Se'irim of Yom Kippur, the two lambs of a Metzora, and the two birds of a Metzora, the words "Shenayim la'Yom" cannot teach that the Kisvei Temidin, the two lambs offered each day for the morning Tamid and the afternoon Tamid, must be identical. RASHI explains that since no Mishnah mentions such a requirement, it must be that no such requirement exists. The Gemara concludes that the words "Shenayim la'Yom" are used for a different Derashah.
What does Rashi mean when he says that since no Mishnah mentions the requirement, no such requirement exists? The Gemara continues and says that the two animals offered as the Korban Musaf on Shabbos must be identical, even though no Mishnah mentions that requirement. Why must the Musafin be identical, but not the Temidin? (TOSFOS)
(a) TOSFOS (DH Musafin) answers that since the Mishnayos in Maseches Tamid detail the entire order of the daily Tamid service, the Mishnah should mention the requirement that the two Temidin be identical if such a requirement exists. The fact that the Mishnah makes no mention of it clearly indicates that no such requirement exists. In contrast, the Mishnah does not describe the service of the Korban Musaf in detail, and thus it is possible that the animals must be identical even though the Mishnah makes no mention of it.
(b) The MALBIM (beginning of Parshas Acharei Mos) explains that since there are many Beraisos which teach that the word "Shnei" in a verse implies that the two objects must resemble each other, it is not necessary for a Mishnah to mention that requirement specifically with regard to the Musafin. It is an accepted rule that "Shnei" means that they must be identical.
This rule does not apply to the Temidin. The verse that discusses the Temidin does not use the word "Shnei," but rather "Shenayim." The word "Shenayim" is the independent form of the number two, while the word "Shnei" is the conjunctive form. The independent word "Shenayim" does not necessarily denote that the objects in the verse must be similar. Therefore, Rashi explains that had there been a requirement that the Temidin be identical, a Mishnah (or Beraisa or Midrash) would have taught that even the word "Shenayim" teaches that the objects in the verse must resemble each other.