This is apparent, as the punishment for sacrificing them is stated in this verse: “And he did not bring it to the entrance of the Tent of Meeting, to sacrifice an offering to the Lord, before the Tabernacle of the Lord…that man shall be cut off from among his people.” The prohibition is also explicit, as it is written: “Take heed to yourself lest you offer up your burnt offerings in every place that you see” (Deuteronomy 12:13).

From that point onward, the verse is speaking about sacrificial animals that one consecrated during a period when there was permission to sacrifice offerings on private altars, i.e., before the Tabernacle was erected, and then he sacrificed them outside the Tabernacle during a period when the prohibition against sacrificing on private altars was in effect.

This is apparent, as it is stated: “In order that the children of Israel shall bring their sacrifices, which they slaughter upon the open field, that they shall bring them to the Lord, to the entrance of the Tent of Meeting” (Leviticus 17:5). The phrase “their sacrifices, which they slaughter” is interpreted as referring to offerings that I have previously permitted for you to slaughter on private altars. This verse teaches that those offerings may now be sacrificed only inside the Tabernacle. The phrase “upon the open field” tells you that in the case of one who slaughters an offering on a private altar during a period when the prohibition against sacrificing on private altars is in effect, even if he sacrifices the offering to God, the verse ascribes him blame as if he sacrificed it upon the open field in idolatrous worship.

The verse continues: “That they shall bring them to the Lord.” This is a positive mitzva to sacrifice in the Tabernacle even offerings that were consecrated before the Tabernacle was erected. From where is it derived that there is a prohibition against sacrificing them outside the Tabernacle? The verse states: “And they shall not slaughter anymore their offerings to the se’irim after whom they go astray; this shall be to them an eternal statute, throughout their generations” (Leviticus 17:7).

One might have thought that sacrificing these offerings outside the Tabernacle would be punishable by karet, as is the halakha with regard to offerings consecrated after the Tabernacle was erected. Therefore, the verse states: “This shall be to them an eternal statute, throughout their generations” (Leviticus 17:7). One can infer from this verse that this, the punishment for transgressing a positive mitzva and a prohibition, applies to them, but no other punishment applies to them. It is clear from this baraita that the verse “And they shall not slaughter anymore” is used to teach about the prohibition against sacrificing outside the Tabernacle those offerings that were consecrated while there was permission to sacrifice on private altars, and not those offerings that were consecrated while it was prohibited to sacrifice on private altars.

Rather, Rabbi Avin says: The prohibition against slaughtering an offering outside the Temple is derived through an a fortiori inference: Just as in a case in which the Torah did not prescribe punishment for a certain action, it nevertheless prohibited it, as is the case with regard to sacrificing outside the Temple an offering consecrated while there was permission to sacrifice on private altars, so too, in a case in which the Torah did prescribe punishment for a certain action, as is the case with regard to slaughtering outside the Temple an offering consecrated while it was prohibited to sacrifice on private altars, is it not logical that the Torah prohibited the action?

Ravina said to Rav Ashi: If so, that whenever the Torah states a punishment for a certain action, there is no need for it to state the prohibition, then let the Torah not state a prohibition with regard to eating forbidden fat of a kosher animal, and then derive the fact that it is prohibited through an a fortiori inference from the prohibition against eating an unslaughtered animal carcass: Just as with regard to a carcass, even though the Torah did not prescribe punishment for consuming it, it nevertheless prohibited consuming it, so too, with regard to animal fat, for which the Torah did prescribe punishment, is it not logical that the Torah prohibited its consumption?

Rav Ashi came before Rava and said to him: The prohibition against eating animal fat can also not be derived from the prohibition of a carcass, as the a fortiori inference can be refuted as follows: What is notable about a carcass? It is notable in that it renders other items ritually impure through contact with it. Forbidden fat does not share this stringency. The existence of a unique stringency undermines the possibility of using an a fortiori inference.

Rav Ashi raises the possibility of deriving the prohibition against eating forbidden fat through an a fortiori inference from various other prohibitions that, like forbidden fat, do not carry the stringency of being punishable by karet, and Rava rejects each one. Can one derive the prohibition against eating forbidden fat from the prohibition against eating carcasses of ritually impure creeping animals (see Leviticus 11:41)? One cannot, as what is notable about ritually impure creeping animals? They are notable in that they render other items ritually impure though contact with any amount of them. Forbidden fat does not share this stringency.

Can one derive it from the prohibition against eating the carcasses of ritually pure creeping animals (see Leviticus 11:41), which do not have the capacity to render other items ritually impure? One cannot, as what is notable about ritually pure creeping animals? They are notable in that with regard to their prohibition there is liability for consuming any amount of them. Forbidden fat does not share this stringency, as one is liable only if he eats an olive-bulk of it.

Can one derive it from the prohibition against eating the fruit of a tree during the first three years after its planting [orla] or from the prohibition against eating diverse kinds in a vineyard, for which one is liable only if he eats an olive-bulk of them, just like with regard to animal fat? One cannot, as what is notable about orla and diverse kinds in a vineyard? They are notable in that they are items from which deriving benefit is prohibited. Forbidden fat does not share this stringency.

Can one derive it from the prohibition against eating Sabbatical Year produce, from which benefit is permitted just like with regard to animal fat? One cannot, as what is notable about Sabbatical Year produce? It is notable in that it transfers its sanctity to the money with which it is purchased. Forbidden fat does not share this stringency.

Can one derive it from the prohibition of a non-priest partaking of the portion of the produce that is designated for the priest [teruma]? One cannot, as in the case of teruma there are no circumstances in which its general prohibition was permitted. The prohibition concerning teruma applies broadly, unlike in the case of forbidden fat, where the prohibition applies only to the fat of domesticated animals but not to the fat of undomesticated animals. Rava notes that the possibility of deriving the prohibition against eating forbidden fat from all of those prohibitions can also be refuted based on this claim, as in those cases, too, there are no circumstances in which their general prohibition was permitted.

Rava said: If there is a difficulty for me in accepting Rabbi Avin’s claim that the prohibition against slaughtering an offering outside the Temple can be derived via an a fortiori inference, this is difficult for me: That which we learned in a mishna (Karetot 2a), which enumerates the thirty-six cases for which one is liable to receive karet. The end of that mishna lists: One who neglects sacrificing the Paschal offering and one who does not undergo circumcision, which are positive mitzvot, unlike the other cases enumerated in the mishna, which are all prohibitions.

Rava explains his difficulty: If Rabbi Avin is correct, derive that there is a prohibition against neglecting the sacrifice of the Paschal offering and not undergoing circumcision via an a fortiori inference from the case of one who leaves over sacrificial meat beyond the allotted period for its consumption (see Leviticus 22:30): Just as in the case of one who leaves over sacrificial meat, where the Torah did not prescribe punishment but nevertheless prohibited this act, so too, with regard to neglecting the sacrifice of the Paschal offering and not undergoing circumcision, for which the Torah did prescribe punishment, is it not logical that the Torah actually prohibited neglecting them as well?

Rav Ashi said: I stated this very discussion before Rav Kahana, and he said to me: One cannot derive a prohibition against neglecting the sacrifice of the Paschal offering from the case of one who leaves over sacrificial meat via an a fortiori inference, as it can be refuted: What is notable about one who leaves over sacrificial meat? He is notable in that there is no remedy once the prohibition has been violated. Shall you say the same about the neglect of the Paschal offering, for which there is a remedy? One who fails to bring it on the first Pesaḥ must bring it on the second Pesaḥ.

The Gemara challenges the very premise of Rabbi Avin’s claim: But can one derive that the Torah prohibits an action via an a fortiori inference? Even the one who says that the court administers punishment based on an a fortiori inference concedes that one does not derive a prohibition from an a fortiori inference. Therefore, Rabbi Avin’s claim is refuted.

Rather, the prohibition against slaughtering an offering outside the Temple courtyard can be derived in accordance with the statement of Rabbi Yoḥanan, who says: It is derived from the prohibition against offering up outside the Temple through a verbal analogy between the reference to bringing stated with regard to slaughtering outside the Temple, and the reference to bringing stated with regard to offering up outside the Temple.

With regard to slaughtering, it is stated: “Or that slaughters it outside the camp, and he did not bring it to the entrance of the Tent of Meeting” (Leviticus 17:3–4), and with regard to offering up, it is stated: “That offers up a burnt offering or sacrifice, and he will not bring it to the entrance of the Tent of Meeting” (Leviticus 17:8–9). The verbal analogy teaches that just as there, with regard to offering up, the Torah did not prescribe punishment for an action unless it also explicitly prohibited the action, so too here, with regard to slaughtering, the Torah did not prescribe punishment unless it also prohibited it. Therefore, even though the Torah does not explicitly state the prohibition, it is evident that it is prohibited.