Talmud - Ketubot 34a כתובות ל״ד א׳

It is Rabbi Shimon, who said: The legal status of slaughter that is improper, in that it does not render the meat fit to be eaten, is not that of slaughter. Therefore, one is not liable for slaughter of the animal. The Gemara asks: This works out well with regard to idolatry and the ox that is stoned, as their slaughter is ineffective in rendering the meat fit to be eaten; however, the slaughter on Shabbat is a proper act of slaughter, as we learned in a mishna (Ḥullin 14a): In the case of one who slaughters an animal on Shabbat or on Yom Kippur, although he is liable to receive the death penalty for desecrating Shabbat, his slaughter is valid and the meat may be eaten.

The Gemara answers: The tanna of the baraita under discussion holds in accordance with the opinion of Rabbi Yoḥanan HaSandlar, as it is taught in a baraita:
With regard to one who cooks on Shabbat, if he did so unwittingly, he may eat the food he cooked; if he did so intentionally, he may not eat it at all. This is the statement of Rabbi Meir.
Rabbi Yehuda says: If he cooked unwittingly he may eat at the conclusion of Shabbat, as the Sages penalized even one who sinned unwittingly in that they prohibited him from deriving immediate benefit from the dish that he cooked; if he sinned intentionally, he may not eat from it ever.
Rabbi Yoḥanan HaSandlar says: If he did so unwittingly, the food may be eaten at the conclusion of Shabbat by others but not by him; if he did so intentionally, it may not be eaten ever, neither by him nor by other Jews. According to Rabbi Yoḥanan HaSandlar, food prepared by means of intentional desecration of Shabbat is unfit to be eaten. That is true with regard to cooking food on Shabbat and with regard to slaughtering an animal on Shabbat.

The Gemara asks: What is the rationale for the opinion of Rabbi Yoḥanan HaSandlar? The Gemara explains: It is as Rabbi Ḥiyya taught at the entrance to the house of the Nasi. It is written: “And you shall observe Shabbat, for it is sacred to you; he who profanes it shall be put to death” (Exodus 31:14); just as with regard to a sacred item consecrated to the Temple, eating it is prohibited, so too, with regard to food produced through action that desecrates Shabbat, eating it is prohibited. The Gemara asks: If so, perhaps the analogy should be extended to include the following: Just as with regard to a sacred item, deriving benefit from it is prohibited, so too, with regard to the product of an action that desecrates Shabbat, deriving benefit from it should be prohibited. The Gemara answers: The verse states: “It is sacred to you” (Exodus 31:14), indicating that it shall be yours in the sense that one may derive benefit from it.

The Gemara asks: Based on the analogy between actions that desecrate Shabbat and sacred items, one might have thought that even if the action was performed unwittingly it should be prohibited to eat its product, as is the case with regard to sacred items. Therefore, the verse states: “He who profanes it shall be put to death” (Exodus 31:14), indicating that it is with regard to one who desecrates Shabbat intentionally that I stated to you this analogy to sacred items, as the verse is clearly referring to one who is liable to receive the death penalty, and not with regard to one who desecrates Shabbat unwittingly, who is not executed.

The Gemara comments: Rav Aḥa and Ravina disagree with regard to this matter. One said: The product of an action that desecrates Shabbat is prohibited by Torah law, and one said that it is prohibited by rabbinic law. With regard to the one who said that it is prohibited by Torah law, it is as we said, that it is based on the verse interpreted by Rabbi Ḥiyya. And the one who said that it is prohibited by rabbinic law holds that the verse states: “It is sacred,” from which he infers: It is sacred, but the product of its actions is not sacred, and therefore, by Torah law it may be eaten.

The Gemara asks: And according to the one who said it is prohibited by rabbinic law, what is the rationale for the opinion of the Rabbis who exempt the thief from payment for the slaughter performed by his agent on Shabbat? By Torah law, the slaughter is valid. The Gemara answers: When the Rabbis exempt the thief from payment, it is with regard to the rest of the cases, i.e., one who slaughters for idolatry or an ox sentenced to stoning, not with regard to Shabbat.

The Gemara asks the following question with regard to Rabbi Meir’s opinion that one who slaughters for idolatry is liable to pay the owner for the animal. Once he slaughtered the animal a bit, at the very start of the act of slaughter, it is prohibited for him to derive benefit from the animal because it is an animal sacrificed to idolatry; and when he slaughters the rest, it is not the animal that belongs to its owner that he is slaughtering. Since it is prohibited to derive benefit from the animal, it has no value and there is no ownership. Rava said: It is referring to one who says, prior to the slaughter, that he is worshipping the idol only at the completion of the slaughter, and therefore the prohibition takes effect only then.

The Gemara asks the following question with regard to Rabbi Meir’s opinion that one who slaughters the ox that is stoned is liable to pay for the slaughter. Why is he liable? It is not the owner’s ox that he is slaughtering, since once the ox is sentenced to be stoned it is prohibited to derive benefit from it. Rabba said: With what are we dealing here? We are dealing with a case where the owners entrusted the ox to a bailee and the ox injured another person while in the bailee’s house, and it was sentenced to be stoned while in the bailee’s house, and the thief then stole it from the bailee’s house and slaughtered it.

And this solution is based on the fact that Rabbi Meir holds in accordance with the opinion of Rabbi Ya’akov and holds in accordance with the opinion of Rabbi Shimon. He holds in accordance with the opinion of Rabbi Ya’akov, who said: Even after the ox was sentenced to be stoned, if the bailee returned it to its owners, it is returned. Despite the fact that the ox is now worthless, as no benefit may be derived from it, since the bailee returned an ox that is physically intact the owner has no claim against him. And Rabbi Meir holds in accordance with the opinion of Rabbi Shimon, who said that the legal status of an object that effects monetary loss is like that of money. Even in the case of an object that is worthless, if its elimination causes monetary loss because it must be replaced, it is considered to have value. In this case, although the ox has no value in and of itself, slaughtering the animal prevents the bailee from returning it intact to the owner, requiring him to pay the owner the value of the ox before it was sentenced to be stoned. Consequently, the thief must reimburse the bailee, as the ox has value for the bailee.

Rabba said: Actually, contrary to Rabbi Yoḥanan’s explanation of the baraita, it is referring to one who slaughters the animal himself,

Traduction : The William Davidson digital edition of the Koren Noé Talmud, with commentary by Rabbi Adin Even-Israel Steinsaltz.

Ketuvot 34a explores how Rabbi Shimon and Rabbi Yohanan HaSandlar's views shape rules on slaughtering or cooking during Shabbat desecration.