The Gemara answers that the verse states with regard to the red heifer: “And he shall slaughter it” (Numbers 19:3), and it mentions the term statute: “This is the statute of the Torah” (Numbers 19:2), indicating that with slaughter, yes, the red heifer is rendered fit; with breaking the neck, the red heifer is not rendered fit.

The Gemara asks: And is it so that anywhere that statute is written with regard to a certain matter, we do not learn an a fortiori inference? But what about Yom Kippur, with regard to which statute is written: “And this shall be an everlasting statute unto you” (Leviticus 16:34), and nevertheless it is taught in a baraita: “And Aaron shall bring forward the goat upon which the lot came up for the Lord, and he shall offer it for a sin offering” (Leviticus 16:9). The verse indicates that the lottery renders the goat a sin offering, but a verbal designation of the goat with the status of a sin offering does not render it a sin offering.

The baraita continues: A verse is necessary to teach this halakha, as one might have thought that the opposite conclusion is correct: Could this not be derived through an a fortiori inference: If in a case where the lottery does not sanctify the animal with a specific designation, such as in the case of two birds brought by a woman after childbirth, and nevertheless a verbal designation of that offering sanctifies it, in a case where the lottery sanctifies the animal on Yom Kippur, isn’t it logical that a verbal designation as a sin offering sanctifies it? Therefore, the verse states: “And render it a sin offering;” the lottery renders the goat a sin offering, but a verbal designation of a sin offering does not render the goat a sin offering.

The Gemara infers: The reason that the a fortiori inference is not learned is that the Merciful One writes: “And he shall offer it for a sin offering.” But otherwise we would learn an a fortiori inference, despite the fact that statute is written with regard to the Yom Kippur service.

The Gemara explains: Actually, one may learn an a fortiori inference even in a case where statute is written. Nevertheless, with regard to the heifer whose neck is broken, the Merciful One restricts the use of breaking the neck: “And all the Elders of that city…shall wash their hands over the heifer whose neck is broken” (Deuteronomy 21:6). From the relative pronoun “whose” it is derived: This heifer is killed by breaking the neck, but no other, i.e., the red heifer, is killed by breaking the neck.

The Gemara challenges: And let it be derived that the heifer whose neck is broken is rendered fit with slaughter by means of an a fortiori inference: If a red heifer, which is not rendered fit with breaking the neck, is rendered fit with slaughter, then with regard to a heifer whose neck is broken, which is rendered fit with breaking the neck, isn’t it logical that it is rendered fit with slaughter? The Gemara responds that the verse states: “And shall break the neck of the heifer there in the valley” (Deuteronomy 21:4). The doubled reference to breaking the neck in the two verses indicates that by breaking the neck, yes, the heifer may be killed; by slaughter, the heifer may not be killed.

MISHNA: There is an element with which priests remain fit and Levites are unfit, and there is also an element with which Levites remain fit and priests are unfit.

GEMARA: The Sages taught in a baraita in explanation of the mishna: Priests are rendered unfit for Temple service with the blemishes enumerated in the Torah (see Leviticus 21:16–23), but remain fit with the passage of years, as from the moment that they reach majority they are fit for service for the rest of their lives. Levites remain fit for Temple service with the blemishes enumerated in the Torah but are unfit with the passage of years, as they are fit for service only between the ages of thirty and fifty (see Numbers 4:47). It is found that there is an element with which priests remain fit and Levites are unfit, and there is an element with which Levites remain fit and priests are unfit.

The Gemara asks: From where are these matters derived? The Gemara answers: It is as the Sages taught in a baraita: “This is that which pertains to the Levites” (Numbers 8:24); why must the verse state this? Since it is stated: “And from the age of fifty years he shall return from the service” (Numbers 8:25), we learned with regard to the Levites that the passage of years disqualifies them. One might have thought that blemishes disqualify them too. And ostensibly, it could be learned through logical inference: If priests, with regard to whom the passage of years does not disqualify them, blemishes disqualify them, then in the case of Levites, with regard to whom the passage of years disqualifies them, isn’t it logical that blemishes disqualify them? Therefore, the verse states: “This is that which pertains to the Levites,” from which it is derived: “This,” the passage of years, is a disqualification that pertains to the Levites, and there is no other disqualification that pertains to the Levites.

One might have thought that priests would be disqualified with the passage of years. And ostensibly, could this not be derived through the following a fortiori inference: If Levites, with regard to whom blemishes do not disqualify them, the passage of years disqualifies them, then in the case of priests, with regard to whom blemishes disqualify them, isn’t it logical that the passage of years disqualifies them? Therefore, the verse states: “Which pertains to the Levites,” and not which pertains to the priests.

One might have thought that the Levites were disqualified with the passage of years even in Shiloh, the permanent place of the Tabernacle, and in the eternal Temple. Therefore, the verse states: “To perform the work of service, and the work of bearing burdens” (Numbers 4:47), juxtaposing the two forms of Levite service to teach: I stated the disqualification of the passage of years only at a time when there is Levite service involving carrying the Tabernacle on their shoulders.

The baraita notes that one verse states: “From twenty-five years old and upward” (Numbers 8:24), and one verse states: “From thirty years old and upward” (Numbers 4:47). It is impossible to say thirty, as twenty-five is already stated, and it is impossible to say twenty-five, as thirty is already stated. How can these verses be reconciled? Twenty-five years old is the time for apprenticeship and thirty for service.

From here it is derived that a student who did not see a positive indication in his studies after five years will no longer see a productive result from those studies. Rabbi Yosei says that the period is three years, as it is stated with regard to Daniel and his cohort who instructed the king of Babylonia: “And they should be raised three years” (Daniel 1:5), “and he should teach them the books and the language of the Chaldeans” (Daniel 1:4).

The Gemara asks: And how does the other tanna explain the verses in Daniel? The Gemara answers: He holds that the verses in Daniel cannot be cited as a source for this principle because the language of the Chaldeans is different, as it is easy and can be learned in a shorter period. The Gemara asks: And how does the other tanna, Rabbi Yosei, explain the verses with regard to the Levites? The Gemara answers: He holds that the halakhot of Temple service are different, as they are difficult and require a longer period of study.

The Sages taught in a baraita: A priest, from the time he reaches puberty and grows two pubic hairs until he ages, is fit for Temple service, and blemishes disqualify him. A Levite from the age of thirty until the age of fifty is fit for Temple service, and the passage of years disqualifies him. In what case is this statement said? It is said with regard to the Tent of Meeting of the Tabernacle in the wilderness. But with regard to Shiloh and in the eternal Temple, Levites are disqualified only due to a change in voice that renders them unable to recite the songs in the Temple with their brethren. Rabbi Yosei said: What is the verse from which this is derived?