Talmud - Pesahim 27a פסחים כ״ז א׳

until there is enough of the prohibited leaven to cause the dough to become leavened bread. And Abaye said: Rabbi Eliezer taught that when the permitted leaven fell in last, the mixture is permitted only when he first removed the prohibited leaven before the permitted leaven fell into the dough and made it rise. However, if he did not first remove the prohibited leaven, the dough is prohibited even if the permitted leaven fell in last. Apparently, when both this and that cause the dough to become leavened bread, it is prohibited.

The Gemara rejects this statement: And from where is it apparent that the reason for Rabbi Eliezer’s opinion is in accordance with Abaye’s explanation? Perhaps the reason for Rabbi Eliezer’s opinion is due to the following, which Rabbi Eliezer said explicitly: I follow the final element. And it is no different if he first removed the prohibited item and it is no different if he did not first remove the prohibited item. However, if they both fell in at once it should be permitted, because where both this and that cause the dough to become leavened bread Rabbi Eliezer rules that the mixture is permitted.

Rather, the reference is to the opinion of Rabbi Eliezer with regard to wood from an asheira. As we learned in a mishna: If one took wood from an asheira, it is prohibited to derive benefit from it. With regard to one who lit an oven with the wood, if it was a new oven, it must be broken. If it was an old oven, it may be cooled.

If one baked bread with asheira wood as the fuel, it is prohibited to derive benefit from it. If this bread was mixed together with other bread, and that other bread was mixed with other bread, it is prohibited to derive benefit from all of this bread. Rabbi Eliezer says: He casts the benefit into the Dead Sea [Yam HaMelaḥ]. In other words, one is not required to destroy the entire mixture when the prohibited bread is mixed with a large quantity of other bread. Instead one should designate money equal in value to the value of the original wood from the asheira, and he should destroy this money to offset the benefit he derived from the prohibited wood. The first tanna said to him: Idolatry cannot be monetarily redeemed. Once the bread becomes prohibited, it cannot be redeemed by having its value cast into the Dead Sea. Apparently, the opinion of both Sages, including Rabbi Eliezer, is that when both this permitted object and that prohibited object cause a change to another item, the latter item is prohibited.

The Gemara rejects this conclusion: Say that you heard that Rabbi Eliezer and the first tanna are stringent in this matter with regard to idolatry, whose prohibition is stringent. However, with regard to other prohibitions in the Torah, which are less stringent, did you hear him express this opinion? The Gemara responds to this question: Rather, if it is so that Rabbi Eliezer does not hold the same opinion with regard to other prohibitions, to whom will you attribute this baraita? If it is not Rabbi Eliezer who says this, then who is it? And furthermore, wasn’t it taught explicitly in a baraita: And, similarly, Rabbi Eliezer would prohibit these types of mixtures with regard to all prohibitions in the Torah.

Abaye said: If you say, based on the previously stated opinions, that Rabbi Yehuda HaNasi holds that when both this and that cause, it is prohibited, then the opinion of Rabbi Yehuda HaNasi is identical to the opinion of Rabbi Eliezer, as both state that it is prohibited for this same reason. And if you say that Rabbi Yehuda HaNasi holds that when both this and that cause, it is permitted, and here, where Rabbi Yehuda HaNasi rules that it is prohibited, it is because there is improvement from the wood in the bread itself, then in that case, deriving benefit from any of these earthenware bowls, cups, and flasks that were made in such an oven should also be prohibited, since the improvement from the wood is in them as well. If one were to use such utensils he would be deriving benefit from a prohibited item.

When Rabbi Yehuda HaNasi and the Sages disagree is in a case where an oven and a pot were formed using prohibited wood. According to the one who says that when both this and that cause it is prohibited, it is prohibited to derive benefit from these as well, since the prohibited item was a contributing factor in the initial formation of the object. However, according to the one who says that when both this and that cause, it is permitted, it is permitted to derive benefit from them. This is because one derives benefit from the prohibited oven and pot only once they have been subsequently heated by permitted wood. Therefore, the influence on the pot of the prohibited item is only one component in the preparation of this food.

Some say that even according to the one who says that when both this and that cause, it is permitted, the pot made through the use of prohibited wood is prohibited, since it holds the food inside it before the permitted wood is placed in the oven. Therefore, one derives benefit from the prohibited vessel itself without any contribution from a permitted source.

Rav Yosef said that Rav Yehuda said that Shmuel said: With regard to an oven that one lit with peels of orla fruit, or with straw of grain that was planted in a prohibited mixture of diverse kinds in a vineyard, if it is a new oven, it must be shattered. If it is an old oven, it may be cooled. If one baked bread in it, Rabbi Yehuda HaNasi says: The bread is permitted, and the Rabbis say: The bread is prohibited. The Gemara challenges: Wasn’t the reverse taught in the baraita? The Gemara answers: Shmuel teaches the reverse, that it is Rabbi Yehuda HaNasi who permits one to derive benefit from this bread even in the previously mentioned baraita.

And if you wish, say: Shmuel accepts the original text of the baraita that Rabbi Yehuda HaNasi is the one who prohibits deriving benefit from the bread. And generally, Shmuel holds that the halakha is in accordance with the opinion of Rabbi Yehuda HaNasi over his individual colleague who disagrees; however, the halakha does not follow him over several of his colleagues who disagree. And in this particular case, the halakha follows Rabbi Yehuda HaNasi even over his colleagues. And Shmuel holds: I will reverse the two sides presented here, in order to establish the Rabbis’ opinion as a prohibition. Therefore, the conclusion will be to rule that it is prohibited, in accordance with the majority opinion. Although in Shmuel’s version the attributions of the opinions are technically inaccurate, the benefit is that when people see that the Rabbis rule that it is prohibited in this case, they will be inclined to accept their majority opinion, which is the correct halakha.

It was taught as part of the previously stated halakha that if one cooked the bread over coals produced from an asheira, everyone agrees that the bread is permitted. The Gemara records a dispute: Rav Yehuda said that Shmuel said one opinion, and Rabbi Ḥiyya bar Ashi said that Rabbi Yoḥanan said another opinion. One of them said: They taught this leniency only when one cooks with dim coals, whose heat is merely a remnant of the earlier lighting; however, when one cooks with glowing coals, the bread is prohibited. And one of them said: Even when the coals are glowing, the bread is also permitted.

The Gemara asks: Granted, according to the one who said that baking with glowing coals renders the bread prohibited, this is because there is improvement from the prohibited wood in the bread. However, according to the one who said that even when baking with glowing coals the bread is permitted, since they are no longer considered to be wood, where do you find the case where Rabbi Yehuda HaNasi deems bread to be prohibited because there is improvement from the prohibited wood in it? Why should there be a difference between glowing coals and actual burning wood? Rav Pappa said: The case is when a flame is directly opposite the bread. When he cooks the bread directly in front of the wood, it is improved directly by the wood. When the coals are merely glowing, there is no direct benefit from the wood.

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

Pesachim 27a explores mixtures of forbidden and permitted leaven, plus a debate on bread baked using wood from an asheira.