OPINIONS: The Mishnah (13b) states that one is forbidden to sell Levonah (frankincense) to an idol-worshipper, since it is likely that he will use the Levonah to serve his idol. The Gemara quotes a Tosefta which teaches that one is permitted to sell a large quantity, a "bundle" (Chavilah), of Levonah to an idol-worshipper. RASHI explains that since he is buying a large bundle, he probably wants it for commercial purposes and not for idol-worship.
The Gemara asks that perhaps the idol-worshipper who is buying the bundle of Levonah will then go and sell some of it to others who will use it for Avodah Zarah, and, therefore, why is a Jew permitted to sell to an idol-worshipper even a large quantity? Abaye answers that the Torah forbids one from causing another person to sin -- "v'Lifnei Iver Lo Siten Michshol" -- "Do not place a stumbling block before the blind" (Vayikra 19:14), but it does not forbid one from causing another person to cause another person to sin ("Lifnei d'Lifnei").
What is the basis for the leniency of "Lifnei d'Lifnei"? Is the reason for this leniency the fact that the idol-worshipper might not actually sell the Levonah to someone who needs it for Avodah Zarah? Perhaps even when the one who buys it from the idol-worshipper intends use it for Avodah Zarah, the Jew still is permitted to sell it to the first idol-worshipper because there is no indication in the verse to differentiate.
(a) TOSFOS (14b, DH Chatzav) discusses selling books normally used for Avodah Zarah to ordinary Nochrim who are not priests. He says that selling such books to Nochrim is prohibited because the first Nochri buyer "definitely" will give it or sell it to a priest. This is also the opinion of the SEMAG (Lo Ta'aseh 45) and the HAGAHOS MAIMONIYOS (Hilchos Avodas Kochavim 9:6). The BACH (YD 139) points out that these Rishonim maintain that the allowance of "Lifnei d'Lifnei" applies only when the second person will not definitely transgress the prohibition.
(b) The TERUMAS HA'DESHEN (#299) apparently disagrees with the ruling of Tosfos. He discusses the following question. There is a dispute among the Rishonim with regard to whether Nochrim are prohibited from castrating animals. According to the opinion that they are prohibited, may one sell animals to Nochrim when he knows that they will castrate them? The Terumas ha'Deshen suggests that there is reason to permit it. Since the buyer himself does not castrate the animal but rather he gives the animal to his servants who perform the castration, it is a case of "Lifnei d'Lifnei." (One cannot ask that perhaps this case is not a case of "Lifnei d'Lifnei" but a case of "Lifnei" since the servant acts as the agent, Shali'ach, of the buyer, because according to the Halachah a person cannot designate a Shali'ach to perform a sin, and, furthermore, a Nochri cannot appoint a Shali'ach altogether.)
However, the Terumas ha'Deshen concludes by saying, "Nevertheless, one may differentiate between this case and the case of Levonah (the case of the Gemara here)." What does the Terumas ha'Deshen mean by this statement? What is the difference between selling an animal to a Nochri who will give the animal to his servants to castrate, and selling Levonah to a Nochri who will sell it to an idolater who will use it for Avodah Zarah?
The Bach explains that the Terumah ha'Deshen refers to the difference that Tosfos says. In the case of selling an animal to a Nochri, the castration definitely will happen, and thus "Lifnei d'Lifnei" does not permit it, while in the case of selling Levonah, there is no certainty that the Nochri buyer will sell the Levonah to someone who will use it for idolatry.
The KESAV SOFER argues with the Bach and says that this is not the intention of the Terumas ha'Deshen. The Terumas ha'Deshen (in Pesakim #27) explicitly argues with Tosfos with regard to selling books to an ordinary Nochri who will give them to a priest, and he writes that it is permitted because of "Lifnei d'Lifnei"! It is clear that the Terumas ha'Deshen argues with the reasoning of Tosfos.
The Kesav Sofer explains instead that the difference between the case of selling an animal and the case of selling Levonah is that in the case of selling Levonah, the Nochri who buys the Levonah does not have intention to sin with the object; rather, he is simply buying merchandise in order to sell it to make a profit (the same applies in the case of selling books to a Nochri). Although it is almost certain that another Nochri will sin as a result of the object being sold to the first Nochri, that sin is too far removed from the original seller to make his act of selling prohibited. In the case of selling an animal, the Nochri buyer himself intends to do the sin of castrating the animal. Although he will not be the perpetrator of the act, selling the animal to him is akin to ensuring that his servant will castrate the animal. This is why the Terumas ha'Deshen asserts that this case is not similar to the case of Levonah. The SEDEH CHEMED (Ma'arachah 6, 26:24) has a similar understanding of the Terumas ha'Deshen.
The REMA (YD 139:15) understands that the Terumas ha'Deshen remains with his view that "Lifnei d'Lifnei" is permitted even when the secondary party will definitely commit the sin. The SHULCHAN ARUCH there seems to rule in accordance with the minority opinion that there is no prohibition at all to sell books to any Nochri (seemingly even to priests; see BI'UR HA'GRA who is perplexed by the Shulchan Aruch's decision not to even mention the other opinions). The Rema there cites the opinion of Tosfos that one may not sell such books to any Nochri, and he then writes that the Terumas ha'Deshen says that selling them to an ordinary Nochri is permitted. The Rema concludes that one who is stringent and follows the view of Tosfos will be blessed. The Rema clearly understands that the Terumas ha'Deshen indeed argues with Tosfos, and that me'Ikar ha'Din the Halachah follows the view of the Terumas ha'Deshen.
However, the Rema elsewhere seems to contradict this ruling. With regard to the Halachah of selling animals to Nochrim, the Rema (EH 5:14) cites both opinions, and he writes that if the Nochri buyer will not do the castration himself, then "everyone agrees that [selling the animal to him] is permitted." How can the Rema say that this is permitted according to everyone? The Rema himself (in YD 139:15) cites opinions who argue and say that such an act does not qualify as "Lifnei d'Lifnei"!
The Kesav Sofer answers that the Rema means that since most Poskim rule leniently with regard to whether the prohibition of castration of animals applies at all for Nochrim, and the Terumas ha'Deshen prefers to permit selling animals to a Nochri, there is no reason to be stringent in practice. The Kesav Sofer agrees that this is not an entirely satisfactory answer, because this is not the straightforward meaning of the words "everyone agrees." (Also, there are other opinions who rule stringently in both respects, such as the SEMAG, who rules that Nochrim may not castrate animals, and who rules like Tosfos that one may not sell an object to a Nochri which he definitely will give to another Nochri who will sin with it.) (Y. MONTROSE)


QUESTION: The Mishnah states that whether or not one may sell a Behemah Dakah (a small, domesticated animal, such as a sheep) to a Nochri depends on the custom of the place. Where the custom is to sell such an animal to a Nochri, one may follow the custom and sell it. Where the custom is not to sell such an animal to a Nochri, one may not sell it.
The Gemara (15a) concludes that everyone agrees that even in a place in which the Nochrim are suspected of bestiality when they are alone with an animal, one is permitted to sell an animal to a Nochri because a Nochri is careful not to have relations with his own animal, lest he weaken the animal.
If there is no concern that a Nochri will have relations with an animal he buys, then why are there places in which one is prohibited from selling an animal to a Nochri?
(a) The RAN here explains that the custom, in some places, not to sell a Behemah Dakah to a Nochri is based on a different reason. The Mishnah later (22a) states that a person is not allowed to leave his animals with a Nochri, because the Nochri is suspected of having relations with animals, and thus leaving one's animals with a Nochri constitutes "Lifnei Iver Lo Siten Michshol." In order to ensure that no Jew ever transgresses the Isur of "Lifnei Iver," the custom arose never to sell an animal to a Nochri, even when Nochrim became careful not to weaken their own animals by having relations with them.
The SEDER YAKOV questions the Ran's explanation. According to the Ran, the custom was established not to sell animals to Nochrim in order to ensure that no one transgresses the prohibition of "Lifnei Iver." However, the Gemara later (22b) states that Nochrim also have such a temptation with regard to birds. According to the Ran's understanding, a custom not to sell birds to Nochrim also should have developed!
The Seder Yakov answers that perhaps there indeed was such a custom not to sell birds to Nochrim. This custom is not mentioned in the Mishnah simply because it is not the manner of the Mishnah to include every possible case ("Tana v'Shiyer"). Alternatively, even though such a reason technically may exist to prohibit selling birds to Nochrim, since it is an uncommon form of transaction the Rabanan did not establish a custom not to sell birds to Nochrim.
(b) The RITVA explains that although Rebbi Elazar states that Nochrim are careful not to have relations with their own animals lest the animals become weak, not everyone relied on this general assumption. In some places, the Jews still suspected that there was a problem of "Lifnei Iver," and therefore they did not sell any animals to the Nochrim. The Ritva adds that although Rebbi Elazar's reasoning is sound, the custom to be stringent falls in the category of "things which are permitted but the custom is to be stringent." Since the Halachah prohibits one from acting leniently in a place in which the custom is to be stringent, everyone in that place is bound by the custom. TOSFOS also seems to learn like the Ritva (see, however, TOSFOS REBBI AKIVA EIGER in Pesachim (4:3) for an alternative explanation of Tosfos).
(c) RASHI in the Mishnah (DH Makom) writes that the custom to sell a Behemah Dakah to a Nochri exists only in a place where there is no suspicion that the Nochri might have relations with the animal. The MAGID MISHNEH (Hilchos Shabbos 20:5) understands that Rashi explains as the Ritva does. The LECHEM SESARIM understands that Rashi follows the view of the Ran.
However, Rashi himself in Pesachim (53a) explicitly explains like neither of those Rishonim. He explains that the custom in some places not to sell a Behemah Dakah to a Nochri was instituted in order to prevent them from selling a Behemah Gasah to a Nochri. This opinion is also quoted by the BARTENURA in Pesachim (4:3), the ESHKOL, and the ME'IRI. (Y. MONTROSE)