The Gemara discusses whether one is allowed to commit a sin in order that his friend should not, but how far do we take this, and is it always permissible?
במאי קמיפלגי? רבי סבר: ניחא ליה לחבר דלעביד הוא איסורא קלילא ולא ליעבד עם הארץ איסורא רבה. ורבן שמעון בן גמליאל סבר: ניחא ליה לחבר דליעבד עם הארץ איסורא רבה, ואיהו אפילו איסורא קלילא לא ליעבד (דף לב:
The Gemara asks: With regard to what Rebbe and Reb Shimon ben Gamliel disagree? The Gemara answers: Rabbe holds: It is preferable to a Cḥaver that he commit a minor aveira, namely separating Maaser from produce that is not adjacent to the produce they seek to exempt, so that an am ha’aretz will not commit the major aveira of eating tevel on his account. And Rabban Shimon ben Gamliel is of the opinion that: It is preferable to a Cḥaver that an am ha’aretz commit a major aveira, and that he himself not commit even a minor aveira.
Tosfos asks the following question: How can Rebbe say it is preferable to a Cḥaver that he commit a minor aveira, so that an am ha’aretz will not commit the major aveira. For the Gemara in Shabbos (4a) tells us that we do not tell a person to commit a sin in order to save his friend (the Gemara there is discussing a case where one placed bread in an oven, if his friend takes it out before it bakes he will save him from transgressing Shabbos, although he would need to transgress a small sin by removing the bread)?
Tosfos gives two answers: The first is that in this case, ultimately the Chaver is at fault for causing the am ha’aretz to sin, for he sent him to go and eat the produce which is tevel. Therefore in a case where one is at fault for another’s sin, there he is allowed to transgress a small sin to save his friend from a greater sin. The second answer is that unlike the case in Shabbos, here the am ha’aretz did nothing wrong, for he did no action to implicitly bring upon himself the sin. Which is why we allow someone else (and not necessarily someone who caused him to sin) to save him. The case in Shabbos is in regard to someone who went and put the bread in the oven too close to Shabbos, since he should not have done that action which may lead him to transgress Shabbos, no one is allowed to sin even a small aveira to save.
In the poskim, we find various interesting cases where they allowed for someone to do small aveira to save himself or another from a larger aveira, and in most of these cases, we can explain them according to Tosfos understanding that it is only permitted if either you caused him to sin or he did nothing wrong.
One example is what is brought in the Shut Yehuda Yaleh (Asad, siman 115). He discusses a case where a certain Rabbi permitted goose liver which was broiled and cooked but it was not cut across before in the proper way to drain the blood. Now although Rabbi Yehudah Asad felt it was forbidden to eat, when he was asked by one of his students what he should do, he told him not to tell anyone except the Rabbi that he was wrong. The reason he gives is that if he would go public and inform everyone how the Rabbi erred he will most certainly cause the disgrace of a Talmud Chochem and a Chillul Hashem. Although some people will now be transgressing a rabbinic sin by eating the goose liver, it is preferable for them to transgress the small aveira then allowing the sin of Chillul Hashem which is forbidden d’orayso. This can be understood according to the second explanation Tosfos gives, where it is permitted to sin a small sin if it is to save another who did nothing wrong to bring upon himself the greater sin.
Another case is brought in the Sefer Maadanei Shlomo (Fried page 122). It is said there that Rabbi Shlomo Zalman held that if the Eiruv rips on Shabbos in a town where there are many non-religious Jews, it should not be announced for the public that it is forbidden to carry. The reasoning for this is that if it is announced the non-religious people will still carry and therefore transgress the greater sin of carrying with intention. It is preferable not to inform anyone and for it will mean they are not transgressing the Shabbos on purpose (Rabbi Shlomo Zalman explains that this is actually not a shogeg rather is a misaseik). We find this idea in many places, however here there is an additional Chiddush. For this is all fine when it comes to the non-religious who will carry even if they know it’s forbidden, which is why we say better not to tell him and limit the sin. A religious person who will stop carrying if he knows the Eiruv is ripped, and would wish to be informed if he is not allowed to carry. If so, why should the religious person have to transgress the sin of carrying-albeit the smaller sin as it is unintentional in order to save the non-religious person from the greater sin of carrying with intention. This would be a further example of where we would expect for one to sin to save another from a greater sin, although in this case it would be difficult to apply either of Tosfos’s explanations.
The Ritva gives a different answer to explain why this Gemara is not contradicting the Gemara in Shabbos. For in truth here the Chaver did it by his own understanding and did not ask if you are allowed to do so or not. The case in Shabbos is what the Beis Din would tell us to do in the correct way.
I heard from the Sanzer Rebbe Shilta that according to the Ritva, it does not mean that what the Chaver did was wrong. Rather this idea that one is allowed to sin to save another is only for someone one a great level of spirituality who is truly ready to sacrifice his lot in the world to come for another Jew. Only someone who is on such a level may do so, which is what the Ritva means to say that the chaver did it on his own accord, for no Beis Din would be able to answer to him that it is permitted since this is not the case for the general public.
The Sanzer Rebbe brought further proof to this idea from Rashi in Shabbos. Rashi explains that it is talking about someone who comes to ask the Rabbis what he should do. Why did Rashi have to add this? Is every case that Chazal mention a law, only where a person came to ask what he should do? The Sanzer Rebbe explained that Rashi is of the same opinion as that of the Ritva where one may voluntarily transgress a sin to save another. This is why Rashi explains the case where someone came to ask what he should do, for in a case where someone asks, the Bais Din has to tell him what he is supposed to do, for this is in reality the law that one is not supposed to do so. However, if this person feels that he is willing to do so and sacrifice his lot to save another, then he may choose to do so as it is evident from our Gemara.
With this understanding we can understand many stories where we find many tsaddikim who were willing to put themselves in a situation where they would be required to do an aveira in order to save another. One example is by Esther HaMalka, she knew that if she enters the room of Achashverosh she would be transgressing a sin, as Rashi in Esther (4:16). However she was willing to do so to save all the Jews. Although one may not transgress any of the three great sins to save themselves or another, if so why was she allowed to do so? With the Ritva’s understanding we can explain that whilst the Bais Din would not tell a person they are allowed to do so, however if a person is one such a great level that he is willing to sacrifice his lot in the world to come for another they may choose to do so.
I would venture to say, that if a person is truly happy to give away all of his Olam Habah for another, they will find a much greater lot in the world to come waiting for them.