GEMARA: In stating: If the priests and Levites rendered exempt the firstborn children and donkeys of the Israelites in the wilderness from being counted firstborns, the mishna indicates that the priests and Levites themselves rendered the animals exempt. The Gemara therefore asks: Did they render the firstborn children and donkeys exempt? With regard to a person, i.e., the Israelite firstborn, the person, i.e., the priests and Levites, rendered them exempt. But with regard to an animal, i.e., the firstborn donkeys of the Israelites, the animal, i.e., the sheep of the priests and Levites, rendered them exempt, as it is written: “Take the Levites in exchange for all the firstborn among the children of Israel, and the animal of the Levites in exchange for their animals” (Numbers 3:45).

The Gemara answers: Abaye said this is what the mishna is saying: The firstborn animals of priests and Levites are exempt from firstborn status, and that is derived from an a fortiori inference: If the animals of the Levites, i.e., the sheep of the priests and Levites, rendered the firstborn status of the animals of the Israelites in the wilderness abrogated, it is only logical that the sheep of the priests and Levites should render the firstborn status of the priests’ and Levites’ own firstborn donkeys abrogated.

Rava said to him: How can you interpret the a fortiori inference in the mishna as referring to the animals of the priests and Levites? But doesn’t it teach: They, i.e., the priests and Levites, rendered the firstborn children and donkeys of the Israelites exempt? The reference is clearly to the priests and Levites themselves, not their animals.

Furthermore, if it is so that their animals are exempt due to the a fortiori inference, then the priests and Levites should be exempt even from the halakhot pertaining to a male firstborn of a kosher animal, as their firstborn kosher animals rendered the firstborn kosher animals of the Israelites exempt from firstborn status. Why did we learn in the mishna (13a): The priests and Levites were not exempted from the mitzva of the male firstborn of a kosher animal; rather, they were exempted only from redemption of the firstborn son and the firstborn donkey?

Rather, Rava said this is what the mishna is teaching: Priests and Levites rendered themselves exempt, and that is derived from an a fortiori inference: If the sanctity of the Levites abrogated the sanctity of the firstborn of the Israelites in the wilderness, should it not abrogate the sanctity of the firstborn Levites themselves?

The Gemara asks: We have found a source for the halakha that the Levites’ personal status as firstborns is abrogated; from where do we derive that their non-kosher animals, i.e., donkeys, do not have the status of firstborns? The Gemara answers that the verse states: “Yet you shall redeem the firstborn of man, and the firstborn of non-kosher animals you shall redeem” (Numbers 18:15). The status of the human firstborn is juxtaposed with that of a non-kosher animal, from which the following principle is derived: Anything that applies to a woman’s firstborn son applies to the firstborn of a non-kosher animal, and anything that does not apply to a woman’s firstborn son does not apply to a non-kosher animal. Therefore, just as firstborn status does not apply to Levites, it does not apply to their donkeys, and they do not need to be redeemed.

Rav Safra said to Abaye: According to your opinion, that you say the animals of the Levites did not have firstborn status due to the a fortiori inference, then with regard to a Levite who had a lamb, which abrogated the sanctity of the firstborn donkeys of the Israelites, let the firstborn status of his animals be abrogated. But with regard to one who did not have a lamb that would abrogate their sanctity, the status of his animals should not be abrogated.

Rav Safra asked Abaye an additional question: According to both you and Rava, since you agree that the firstborn Levites themselves were exempt from being accorded firstborn status because they rendered the sanctity of the Israelite firstborns abrogated, one should conclude that only a firstborn Levite who was at least one month old, who abrogated the sanctity of the Israelite firstborns (see Numbers 3:15), should have his own firstborn status abrogated. But those firstborn Levites who were less than one month old, who did not abrogate the sanctity of the Israelite firstborns, should not have their own firstborn status abrogated.

Furthermore, the sanctity of a firstborn son born to a female Levite who was married to an Israelite should not be abrogated, as the women were not included among the Levites who were exchanged for the Israelite firstborn. Why, then, does Rav Adda bar Ahava say: With regard to a female Levite who gave birth,her firstborn son is exempt from the obligation of giving five sela coins to the priest to be redeemed?

The Gemara answers the last question: That is not difficult, as it is in accordance with the statement of Mar, son of Rav Yosef, in the name of Rava, who says: The fact that the Torah states with regard to the sanctity of the firstborn: “Firstborn of the womb” (Exodus 13:12), indicates that the Merciful One renders the obligations of firstborn status dependent on being the firstborn of the womb, i.e., of the mother. Therefore, the mother’s status as a Levite is sufficient to exempt the child from firstborn status.

Rav Safra again challenged the opinions of Abaye and Rava: And Aaron, who was not included in that count of the Levites when they were compared to the number of Israelite firstborns and redeemed from their sanctity as firstborns, should not have his own firstborn status abrogated. As it is taught in a baraita: Why do dots appear over the word “Aaron” in the verse in the book of Numbers: “All that were numbered of the Levites, whom Moses and Aaron numbered” (Numbers 3:39)? It is in order to demonstrate that he was not included in that count of the Levites.

The Gemara answers that the verse states: “The Levites” (Numbers 3:45), to teach that all of the Levites were juxtaposed with each other. Therefore, even a firstborn Levite who did not abrogate the sanctity of the Israelite firstborns himself was still abrogated of his own firstborn sanctity.

The Gemara asks: From where do we derive that priests, including Aaron, were also subject to that halakha? The Gemara answers: It is in accordance with the statement of Rabbi Yehoshua ben Levi, as Rabbi Yehoshua ben Levi says: In twenty-four places in the Bible the priests are called Levites, and this is one of them: “But the priests the Levites, the sons of Zadok” (Ezekiel 44:15). It is derived from this verse that priests are included in the category of Levites even where they are not mentioned explicitly.