Megillah 5a: Rav said: “When Purim is observed in its regular time, an individual alone may read the Megillah, but when it is observed outside of its regular time, such as when it falls on Shabbos and is pushed back to Friday, one must read the Megillah with a minyan.”

But does this not contradict the following statement of Rav: “When Purim falls on Shabbos, Friday is the regular time.” Actually, Shabbos is the regular time. (Rashi: Because the Anshei Knesses Hagedolah ordained Purim on Shabbos, and it was only a later generation of sages who made the decree not to read the Megillah on Shabbos.) So when it says Friday is the regular time, doesn’t it mean that one does not need a minyan on Friday? – No. it just means that Purim is not pushed back to Thursday.

This Gemara is discussing the case when the 14^th of Adar fell on Shabbos, but the Mishnah Berurah (690:61) extends the rule (that when it is not the regular time, we need a minyan) to the case when the 15^th of Adar falls on Shabbos and the Megillah is read in a walled city on Friday. 

מגילה ה ע”א. אמר רב: מגילה, בזמנה ־ קורין אותה אפילו ביחיד, שלא בזמנה ־ בעשרה… ומי אמר רב הכי? והאמר רב יהודה בריה דרב שמואל בר שילת משמיה דרב: פורים שחל להיות בשבת ־ ערב שבת זמנם. ־ ערב שבת זמנם? והא שבת זמנם הואִ! אלא לאו הכי קאמר: שלא בזמנם ־ כזמנם, מה זמנם אפילו ביחיד, אף שלא בזמנם ־ אפילו ביחידִ ־ לא… לאפוקי מדרבי וכו’.

שו”ע או”ח תר”צ. מגילה בי”ד ובט”ו צריך לחזור אחר עשרה ואם אי אפשר בעשרה קורים אותה ביחיד. וכתב המ”ב: דהיכא דמתרמי יום ט”ו בשבת דצריכין המוקפין להקדים ולקרותו בע”ש בודאי צריך לקבץ עשרה לקריאתו, ובזה עוד חמיר יותר דאי ליכא עשרה לא יברכו המוקפין עליה.

Once, in Yerushalayim in a year when the 15^th of Adar fell on Shabbos, and the Megillah was read on Friday, the baal korei in one particular shul fell suddenly ill after the reading, and died on Friday afternoon. Rabbi Shlomo Zalman Auerbach paskened that all those who had heard the Megillah from him would have to hear it again. The reason is that the real time for Krias Hamegillah is Shabbos, and Friday is just a replacement for Shabbos. This baal korei, since he did not live to see Shabbos, was not obligated in the mitzvah, and thus was incapable of being “motzi” the listeners in their obligation.

 [The Chazon Ish disagreed with the Mishnah Berurah’s contention that when a walled city pushes back the reading to Friday, they must have a minyan. He argues that since Friday is the day everyone in the world is reading the Megillah, there is enough pirsumei nisa and one doesn’t need a minyan.

But it would seem that in R’ Shlomo Zalman’s case, even the Chazon Ish would agree that the listeners did not fulfill their obligation with the now-deceased baal korei. For even the Chazon Ish agrees that Shabbos is the real time originally ordained for the reading, and Friday is just a replacement for Shabbos. The fact that this replacement time happens to be the time when the rest of the world is laining does not change the fact that it is, after all, just a replacement. And someone who is not obligated in the original day is not obligated in the replacement either.]

Source: Rabbi Aryeh Golovenzitz

Megillah 21b: The Targum should not be read publicly by two people in unison (Rashi: because two voices cannot be heard) but Hallel and the Megillah can be read even by ten people in unison. Why? Since it is beloved to the listeners, they will pay attention and hear.

מגילה כא ע”ב: תנו רבנן: בתורה אחד קורא ואחד מתרגם, ובלבד שלא יהא אחד קורא ושנים מתרגמין. (פירש רש”י וטעמא משום דתרי קלי לא מישתמעי.)  ובנביא אחד קורא ושנים מתרגמין, ובלבד שלא יהו שנים קורין ושנים מתרגמין. ובהלל ובמגילה ־ אפילו עשרה קורין ועשרה מתרגמין. מאי טעמא? כיון דחביבה ־ יהבי דעתייהו ושמעי.

Rabbi Yaakov Yitzchok Ruderman, in a conversation with some Torah educators, graduates of Yeshivas Rabbeinu Yisroel Meir Hakohein, noted the special stress Slabodka Yeshiva put on interpersonal relations, and told the following story. (It was apparent in his tone that he was unsure whether to tell the story to his interviewers – but he did.) In the 5690’s (1930’s), he was once invited to spend a Shabbos at the home of the Rav of Elizabeth, New Jersey. Before the arrival of Shabbos, the rav took him aside for a confidential exchange of words. He told his guest that he had several daughters eating at the Shabbos table who enjoyed Shabbos by singing the zemiros along with him. (At this point in the narrative, R’ Ruderman interjected that there were no Bais Yaakov schools in America at the time – indicating that Bais Yaakov graduates would know better than to do this.) The rav told him that R’ Boruch Ber Leibowitz had been a guest at his home sometime earlier, and when the girls began singing, he stood up and ran out of the room – perturbing the Shabbos for the girls and humiliating their father. The host then asked whether R’ Ruderman would do the same. The guest replied that with his Slabodka background, he would not destroy the family’s Shabbos spirit or embarrass his host; he would remain sitting and not listen to the girls. “My frumkeit does not have to hurt others,” he concluded.

[In Kol Isha there are two separate prohibitions: 1) hearing it, and 2) saying holy words and prayers while hearing it. For a father, the first is not a problem – a father is allowed to hear his daughters sing. Only the second problem exists. But a guest has to contend with both problems.

The Otzar Haposkim Even Ho’ezer 21 brings that the Chasan Sofer permitted listening to a man and woman sing together, because of the principle of our Gemara that “two voices cannot be heard.” In response to the argument that a woman’s voice is חביבה because it is attractive, he argues that one only becomes attracted to her after hearing her sing, but since he cannot hear her sing due to the principle that “two voices cannot be heard,” the problem doesn’t  begin.

The Otzar Haposkim then brings the Be’er Yehuda, who argues based on Rashi in Rosh Hashanah 27a that the reason why “two voices cannot be heard” is because they do not speak exactly in unison; one is always a little ahead of the other. But when they are singing, everyone sings together and they can be heard.

Moreover, it would seem that the Gemara uses this principle as a chumra, not a kula. The Gemara is not saying that when two people read from the Torah, the listeners will never hear a single word. They will probably catch a few words here and there, but they cannot fulfill their obligation that way. But when a woman is singing with a man, and you are looking to be lenient and allow a guest to listen based on “two voices cannot be heard” – this line of reasoning does not work, since at least some of the time he will hear the woman’s voice.

In light of the above, we could suggest a middle ground between these two opinions: for a father to sing with his daughters would be allowed, since we could say ממה נפשך: either way there is no problem. At the times when the daughters are singing at the exact same time as him, he does not hear them because “two voices cannot be heard” and therefore there is nothing wrong with him saying the holy words of Zemiros. (This logic would not apply to one’s wife singing, since her voice is חביבה to him.) And at the times when they are singing separately from him and he does hear them, there is no problem because he is their father and is permitted to listen to them – since he is not saying holy words at that moment. However, for a guest, no such ממה נפשך argument can be made.  

Regarding the apparent machlokes between R’ Boruch Ber and Rav Ruderman on what to do if already stuck in the situation, we can assume that Rav Ruderman relied on the principle of  אי אפשר ולא קמכוין (פסחים כה ע”ב) – that if one is walking on his way and is being exposed to a forbidden pleasure, if he has no way to reach his goal without passing this place, and he has no intention to derive pleasure, it is allowed. See the Mishnah Berurah 75:17 quoting the Chayei Adam:

 ומ״מ אם הוא בדרך בין העכו״ם או בעיר והוא אנוס שא״א לו למחות כיון דלא מצינו דמקרי ערוה מדאורייתא מותר לקרות ולברך דאל״כ כיון שאנו שרויין בין העכו״ם נתבטל מתורה ותפלה וע״ז נאמר עת לעשות לד׳ הפרו תורתך אך יתאמץ לבו לכוין להקדושה שהוא עוסק ולא יתן לבו לקול הזמר.

The Mishnah Berurah permits even saying holy words while listening to a woman singing because of עת לעשות. The implication is that for being on the road among such people, without saying holy words, we don’t need any special heterim; that is the regular rule of אי אפשר ולא קמכוין. In Rav Ruderman’s case, although it was possible to leave the room or, having been warned, find somewhere else to spend Shabbos, he held that that was considered  אי אפשר since it would be impossible to do so without embarrassing another person.

R’ Boruch Ber, on the other hand, probably held that although personally, he could have been lenient, he hoped that his actions would teach the family that it was unacceptable for girls to sing in front of a stranger. Rav Ruderman, however, realized in retrospect that they had not learned from R’ Boruch Ber and would probably not learn from him either.]

Megillah 13b: Haman said to Achashveirosh, “If a fly falls into a Jew’s cup of wine, he throws out the fly and drinks it, but if my lord the king touches it, he spills it on the floor and does not drink it.”

ואפילו נופל זבוב בכוסו של אחד מהן ־ זורקו ושותהו. ואם אדוני המלך נוגע בכוסו של אחד מהן ־ חובטו בקרקע ואינו שותהו.

The Chasam Sofer (Yoreh Deah 94) tells a story took place in Frankfurt: a chicken flew into a vat of boiling butter and died there. A great rabbi (the Chasam Sofer does not give his name, but some say that it was Rabbi Nosson Adler, the Chasam Sofer’s teacher) ruled that the butter was forbidden and they could not even sell it to non-Jews. So they poured it out onto the street. Afterwards, someone reminded him that the Rema says that any milk and meat mixture that is only Rabbinically forbidden to eat, such as chicken and milk, is permitted to derive benefit from, and therefore may be sold to non-Jews. He replied on the spot, “Yes, it was permitted to derive benefit from the butter, but it was forbidden to sell it to non-Jews, because it absorbed the taste of meat from a live animal.”

The Chasam Sofer comments that it was clear that Rabbi Nosson Adler’s original ruling was not because of meat from a live animal; rather, he had indeed forgotten the Rema’s rule that it is permitted to derive benefit from chicken with milk. But Hashem does not allow a tzaddik to make a mistake, and therefore the ruling turned out to be correct for a different reason. Hashem placed this quick answer in his mouth to save him from embarrassment.

We see from this story, concludes the Chasam Sofer, that live animals can give taste to a mixture. Thus the chicken, while still alive, was giving taste to the butter and forbidding it to non-Jews.

The Chasam Sofer’s student Reb Boruch brought additional proof to this from the Rosh in Avodah Zarah 68b, who cites the words of Haman – that a Jew would drink wine touched by a fly – as proof that cold things do not give taste. But maybe there the fly was alive and therefore could not give taste! From the fact that the Rosh ignores this argument, it would seem that he holds that live animals do emit taste.

However, the Amudei Ohr argues that it is unheard of that an animal or person, simply by touching a hot food, should render it forbidden. Therefore the Steipler (Chullin 5) argues that in Rabbi Nosson Adler’s case, the butter was forbidden because some part of the chicken may have become separated from the chicken while the chicken was still alive. That limb, forbidden to non-Jews, is itself dead, and therefore it can emit taste. But a completely live limb, such a human finger stuck into coffee, would not emit taste and forbid the coffee.

As to the Rosh’s comment on Haman’s words, perhaps the Rosh assumed that the fly in question was dead, but a live fly would indeed not emit taste.