The Gemara asks: And with regard to the opinion of the Rabbis, let us say the Rabbis hold that even a portion of the mouth of the womb sanctifies a firstborn despite the offspring never having touched the entire area. As, if only the entire mouth of the womb sanctifies the firstborn, then in a case where the heads emerged as one, granted that it is impossible for both births to coincide precisely and one certainly emerged first, but in any event there is an interposition, i.e., the head of the other fetus, between each fetus and the mouth of the womb.

The Gemara answers that Rav says: No proof may be drawn from here that a portion of the womb sanctifies a firstborn, as a substance that is in contact with the same type of substance does not interpose. Therefore, each fetus is still considered to be touching the entire womb.

§ The mishna teaches that if a female donkey that had not yet given birth gives birth to a male and a female, and there is uncertainty with regard to which was born first, the owner designates a lamb in case the male was born first, which he keeps for himself. The Gemara asks: But since he keeps it for himself, why do I need him to designate it? The Gemara answers: It is necessary in order to abrogate its forbidden status.

The Gemara comments: Apparently, since prior to the designation the sanctity is not yet abrogated, it is prohibited to derive benefit from the donkey at that stage. If so, whose opinion is expressed in the mishna? It is the opinion of Rabbi Yehuda, as it is taught in a baraita: It is prohibited to derive benefit from a firstborn donkey, in accordance with the opinion of Rabbi Yehuda; and Rabbi Shimon deems it permitted.

The Gemara asks: What is the reason for the opinion of Rabbi Yehuda? Ulla says: Do you have an item that requires redemption and it is nevertheless permitted to derive benefit from it? The Gemara challenges: And is there no such item? But doesn’t a woman’s firstborn son require redemption with five shekels, and it is nevertheless permitted to derive benefit from him? Rather, this is what Ulla means: Do you have an item about which the Torah was particular and requires that it be redeemed specifically with a lamb, and yet it is still permitted prior to redemption?

The Gemara challenges: And is the Torah particular about redeeming a firstborn donkey specifically with a lamb? But didn’t Rav Neḥemya, son of Rav Yosef, redeem a firstborn donkey with boiled vegetables that were worth its full value? The Gemara answers: Ulla is not saying, i.e., referring to, a case where the donkey is redeemed at its full value. Rather, when we say the Torah is particular that the donkey be redeemed with a lamb, the reference is to redeeming it not at its full value, and this is what Ulla is saying: Do you have an item about which the Torah was particular so as to require abrogating its forbidden status specifically with a lamb, if the lamb is worth less than the donkey? Therefore, Rabbi Yehuda holds that deriving benefit from a firstborn donkey is forbidden.

The Gemara challenges: But this contradicts Rabbi Yehuda’s ruling with regard to second-tithe produce, concerning which the Torah was particular about its being redeemed only with a minted coin, and we learned in a mishna that Rabbi Yehuda says: If one betrothed a woman with second-tithe produce, if he did so intentionally, he has betrothed her. Apparently, he maintains that deriving benefit from second-tithe produce is not prohibited prior to redemption.

The Gemara answers: That is not proof, as according to Rabbi Yehuda, if a man betrothed a woman with a firstborn donkey, she is also betrothed. This applies even if deriving benefit from the animal is prohibited, in accordance with the opinion of Rabbi Elazar. As Rabbi Elazar says: The reason a woman is betrothed with second-tithe produce is that she knows that second-tithe produce is not desacralized by her betrothal. Rather, it remains prohibited, and she will subsequently ascend and consume it in Jerusalem, where consumption of second-tithe produce is permitted. She is therefore betrothed with the benefit of that future consumption.

Here too, where one betroths a woman with a firstborn donkey, the betrothal is effective despite the fact that it is prohibited to derive benefit from the animal. This is because a woman knows that a firstborn donkey has a forbidden status and she will therefore redeem it with a lamb. And she is betrothed with that amount, i.e., of the difference between the value of the donkey and the value of the lamb, as the value of the lamb is lower.

The Gemara asks: And as for Rabbi Shimon, what is the reason he holds it is permitted to derive benefit from a firstborn donkey prior to its redemption? The Gemara answers that Ulla says: Do you have an item whereby its redemption, i.e., the item with which it is redeemed, is permitted, but the item itself is forbidden? Here too, since the lamb that is given to the priest is permitted, the donkey that it redeems should have been permitted as well prior to the redemption.

The Gemara asks: And is there not such a case? But isn’t there the case of selling produce from the Sabbatical Year? As its redemption, i.e., the money received in exchange for the produce, is permitted. But deriving benefit from the produce itself is prohibited after that type of produce is unavailable in the fields, as at that time it must be removed from the house as well.

The Gemara answers: With regard to the produce of the Sabbatical Year as well, its redemption is forbidden, as the Master says: If one purchased meat with produce of the Sabbatical Year, both the produce and the meat must be removed during the Sabbatical Year after the point when produce of that kind no longer remains in the field. If one purchased wine in exchange for the meat, the meat’s consecrated status is negated and the wine assumes consecrated status. This process continues until the very last item purchased assumes the consecrated status of the produce of the Sabbatical Year, and the actual produce itself remains consecrated and forbidden following the time of removal.

The Gemara offers an additional basis for the dispute between Rabbi Yehuda and Rabbi Shimon: And if you wish, say that Rabbi Yehuda and Rabbi Shimon disagree with regard to the following verse, as it is taught in a baraita with regard to the prohibition against shearing and working a firstborn kosher animal that the Torah states: “You shall do no work with the firstborn of your ox” (Deuteronomy 15:19), but you may perform labor with a firstborn animal that is both your own and also that of others, i.e., an animal owned in partnership with a gentile. Although firstborn status applies to the Jew’s share in the animal and he must give the value of his share to a priest, nevertheless, it has no sanctity and deriving benefit from it is permitted. The verse continues: “Nor shear the firstborn of your flock,” but you may shear a firstborn animal that is yours and that is also that of others. This is the statement of Rabbi Yehuda.

Rabbi Shimon says the verse should be interpreted as follows: “You shall do no work with the firstborn of your ox,” but you may do work with a woman’s firstborn son, as no prohibition exists with regard to deriving benefit from the labor of a firstborn boy even before he is redeemed. “Nor shear the firstborn of your flock,” but you may shear a firstborn donkey, as deriving benefit from it is permitted. Rabbi Yehuda, who does not interpret the verse in this manner, holds that it is prohibited to shear and derive benefit from a firstborn donkey as well.

The Gemara asks: Granted, according to the opinion of Rabbi Shimon, that is the reason that two verses, i.e., phrases, are written, one that excludes a woman’s firstborn son from the prohibition against deriving benefit and another that excludes a firstborn donkey. But according to Rabbi Yehuda, why do I need two verses to exclude a firstborn animal that is yours and that is also that of others, i.e., owned jointly by a Jew and a gentile, from the prohibition against deriving benefit from the firstborn? And furthermore, according to Rabbi Yehuda, shall we say that deriving benefit from a woman’s firstborn son should also be forbidden, since it was not excluded by any verse?

Rather, everyone agrees that the term “your ox” comes to exclude a woman’s firstborn son, from whom it is permitted to derive benefit. When they disagree, it is with regard to the term “your flock.” As Rabbi Yehuda conforms to his line of reasoning, as he says that an animal that is owned in partnership with a gentile is obligated in a firstborn, i.e., subject to the requirement that its owner count its offspring as a firstborn, and therefore the verse was necessary to permit shearing and using the animal for labor.

And Rabbi Shimon holds that an animal owned in partnership with a gentile is exempt from its offspring being counted a firstborn, and therefore with regard to shearing and labor, no verse was necessary. Rather, the verse was necessary to exclude the case of a firstborn donkey from the prohibition against shearing and working the firstborn animal.

The Gemara asks: Granted, according to the opinion of Rabbi Yehuda, this is the reason that the term “your flock” is written, and not simply the word flock. It excludes sheep that are owned in partnership with a gentile. And with regard to the term “your ox,” the word ox alone is sufficient to exclude a woman’s firstborn son from the prohibition; and the verse employed the term “your ox” because of the term “your flock,” so that the two would be stylistically similar. But according to the opinion of Rabbi Shimon, who derives from the term “your flock” that a firstborn donkey is not included, writing the terms flock and donkey alone would suffice. Why do I need the terms “your ox” and “your flock”? The Gemara concludes: This is difficult.

§ Rabba says: And Rabbi Shimon concedes that even if it is permitted to derive benefit from a firstborn donkey that was not redeemed, following the breaking of its neck in fulfillment of the verse: “And you shall redeem every firstborn donkey with a lamb, and if you do not redeem it, then you shall break its neck” (Exodus 13:13), it is forbidden to derive benefit from its carcass.

What is the reason for this ruling? He derives this halakha by a verbal analogy between the expression: “Breaking the neck,” stated here, and the expression: “Breaking the neck,” stated in the case of the heifer whose neck is broken by the Elders of the city due to a unresolved murder (see Deuteronomy 21:1–9). Just as it is forbidden to derive benefit from the heifer after its neck is broken, so too is it prohibited to derive benefit from a firstborn donkey that was not redeemed following the breaking of its neck.

Rava said: From where do I say that this is the opinion of Rabbi Shimon? As it is taught in a baraita (Tosefta, Okatzin 3:12): The fruit of a tree during the first three years after its planting [orla], and diverse kinds in a vineyard, and the flesh of an ox that was to be stoned for killing or copulating with a person but was slaughtered instead, and that of a heifer whose neck was to be broken but was slaughtered instead, and of the birds offered by a leper (see Leviticus 14:4–7), and of a firstborn donkey whose neck was broken, and meat cooked together with milk, are all susceptible to the ritual impurity of food, despite the fact that their consumption is forbidden.

Rabbi Shimon says: All of them are not susceptible to the ritual impurity of food, since they are all items from which deriving benefit is prohibited and are therefore not considered food. And Rabbi Shimon concedes with regard to meat cooked together with milk that it is susceptible to the impurity of food, since both the meat and the milk had a period of susceptibility to contracting impurity before they were cooked together.

And Rabbi Asi says that Rabbi Yoḥanan says: What is the reason for the opinion of Rabbi Shimon that an item from which deriving benefit is prohibited is not susceptible to the impurity of food? It is as it is written: “All food therein that may be eaten [ha’okhel asher ye’akhel], that on which water comes, shall be impure” (Leviticus 11:34). The use of the Hebrew root alef, khaf, lamed twice in this phrase indicates that specifically food that you are able to feed to others, i.e., gentiles, is called food with regard to susceptibility to the impurity of food. But food that you are not able to feed to others is not called food. Therefore, an item from which deriving benefit is prohibited and which one is consequently forbidden to feed to gentiles is not considered food in this context.