Rambam - 1 Chapter a Day

In Sefer HaMitzvot (Positive Commandment 209), the Rambam counts this as one of the Torah’s 613 mitzvot. (See also Sefer HaChinuch, Mitzvah 257.) In the Guide for the Perplexed (Vol. III, Chapter 36), the Rambam explains the motivating principle for this mitzvah: If respect is not shown to the scholars, their teachings will not be upheld and Torah study will be neglected.

In which case more severe measures of honor are necessary, as mentioned in the previous chapter. The Rama (Yoreh De’ah 244:1) states that this obligation applies only to another scholar who surpasses oneself in knowledge.

Even if he is young. The definition of a Torah scholar is a matter of debate. Kiddushin 49b states:
“On the condition that I am a student” — we do not say that he must be comparable to
Shimon ben Azzai or Shimon ben Zoma. Rather, anyone who can be asked about any
matter in the area where he is studying and can reply....”
On the condition that I am a wise man” — we do not say that he has to be like the
Sages of Yavneh.... Rather, anyone who can be asked about any Torah subject and
can reply...
The Rambam quotes this statement in Hilchot Ishut. Nevertheless, since he does not specify such a definition here, in Hilchot Talmud Torah, one may therefore assume that in this context, he does not limit himself to that definition. The Siftei Cohen (Yoreh De’ah 244:2) addresses himself to this issue and explains that here we are referring to a Torah scholar who possesses a prodigious amount of knowledge and is considered unique within his community.

Kiddushin 33a states that once the scholar comes this close, standing before him can easily be appreciated as a sign of respect. Note the contrast between this halachah and the measure of respect due one’s own teacher, as mentioned in Chapter 5, Halachah 7. Once the scholar passes, one may sit, in contrast to the requirement regarding one’s teacher mentioned in the previous chapter.

I.e., in the inner rooms where people stand undressed. The general principle followed is: in the places where it is permitted to recite words of Torah, one must honor a scholar; where one may not recite words of Torah, one should not honor a scholar (Kessef Mishneh).

And in these places, there is no honor in standing for a person. This law is not mentioned with regard to one’s own teacher, since, as stated in Chapter 5, Halachah 6, one may not enter a bathhouse together with one’s teacher (Rav Kapach).

The commentaries disagree whether a craftsman may interrupt his work to show a scholar this token of respect or not. The Kessef Mishneh states that a craftsman is permitted to do so, and rules accordingly in the Shulchan Aruch (Yoreh De’ah 244:5). In contrast, Rabbenu Nissim (Chulin 54b) maintains that a craftsman is not permitted to stand, because the general impression that will be created — i.e., some craftsmen standing in honor of the scholar and some not — will not be favorable.
This difference of opinion exists only with regard to craftsmen working independently. All authorities agree that a craftsman hired by others may not stand. His time is not his own, and by standing, he steals time from his employer.

The Lechem Mishneh objects to these statements, noting that the Rambam’s phraseology is not an exact quote from Kiddushin 33a, which is his source. Nevertheless, it can be explained that the Rambam is not quoting that Talmudic passage, but rather explaining a concept that can be inferred from it.

Kiddushin (ibid.) states that we would not suspect that a person would fail to honor a scholar when the latter is actually close to him. Rather, this implies that it is forbidden for one to turn away when he sees the scholar approaching from afar, so that when the latter approaches, he will not be obligated to stand.

Who probes man’s heart and understands his inner feelings.

Kiddushin 33b derives this concept through the exegesis of the verse from Leviticus quoted above.

Kiddushin 33a promises a scholar long life for following this practice.

Kiddushin (ibid.) mentions that Abbaye and Rabbi Zeira would follow this practice. The Bnei Binyamin notes an apparent contradiction between the Rambam’s statements and Bamidbar Rabbah 15:17. There, the Midrash relates that Rav Abba Cohen would always avoid crowds, lest he trouble them by causing them to rise. When he mentioned this to Rabbi Yosse, the son of Rabbi Zevida, the latter reprimanded him, explaining that he would be doing them a great favor by having them stand before him, because this would lead to the fear of God, as implied by Leviticus (loc. cit.): “Stand up before a white-haired [man]... and you shall fear your God.”
The Bnei Binyamin explains that everything depends on the scholar’s intention. A righteous man who is not at all motivated by self-interest may appear before crowds. However, a person who is concerned with his own pride should avoid them.

I.e., we do not say that since the scholar is seated on his animal, it is not considered as if he is walking. However, in other contexts — see Hilchot Kri’at Shema 2:2-3 — the Rambam considers riding as comparable to sitting.

Kiddushin 33a relates that Abbaye would stand as soon as he saw the donkey of Rav Yosef, his teacher, approach.

This addition was made on the basis of the Hagahot Maimoniot, who maintains that this law does not apply when each individual is journeying separately, involved in his own affairs.

Following slightly behind him. For one who walks alongside his teacher is considered a boor (Yoma 37a; see Kessef Mishneh and also Chapter 5, Halachah 6 above).

Yoma (loc. cit.) derives this formation from the pattern in which the angels who visited Abraham (Genesis, Chapter 18) walked. This formation was also employed by the High Priest and his subordinates when he would serve in the Temple.
The Pri Chadash and other commentaries question the Kessef Mishneh’s interpretation. One point of difficulty with the halachah in general is that it appears to refer to one’s personal teacher, and thus it would more appropriately have been mentioned in the previous chapter.

This halachah in its entirety is quoted from the Midrash Hagadol, Shmot 33:8. (With slight textual differences, it also appears in Kiddushin 33b.) Nevertheless, the question arises: Why does the Rambam mention this particular clause? It appears redundant in light of Halachah 1. Perhaps his intent was to emphasize the contrast between an ordinary scholar and others of greater stature.

The sage second in stature to the nasi, and who acts as the latter’s assistant (Hilchot Sanhedrin 1:3).

I.e., as soon as the av beit din appears on the horizon.

In Hilchot Sanhedrin (loc. cit.), the Rambam describes this position as follows: The wisest sage among them is appointed to be the head. He is the Rosh Yeshivah. He is the person whom the Sages referred to as nasi in all the sources, taking the place of Moses, our teacher

Kiddushin (loc. cit.) derives this from Exodus 33:8, which relates that: “Whenever Moses went out to the tent, all the people would rise. Each person would stand near his tent, gazing at Moses until he came to the tent.”

I.e., although people are obligated to honor the nasi, should he desire to forgo those honors, there is no objection. In contrast, a king may never forgo his honor and must constantly be treated with reverence. (See Hilchot Melachim 2:3.)
Kiddushin 32b relates the following discussion of this law:
An incident occurred when Rabbi Eliezer, Rabbi Yehoshua, and Rabbi Tzadok were
participating in the wedding feast of Rabban Gamliel’s son, and Rabban Gamliel
poured drinks for them. He offered a cup to Rabbi Eliezer, but he refused to accept it.
He offered a cup to Rabbi Yehoshua and he accepted it.
Rabbi Eliezer told him: “Yehoshua, what is this? We are sitting and Rabban Gamliel
is pouring drinks for us!”
He replied to him: “We find [a precedent where] a person of greater stature served
others. Abraham surpassed all others in his generation, yet [Genesis 18:8] relates that
‘he stood over them [to serve them’]. Do not think that he thought they were angels;
he thought they were Arabs. If so, why shouldn’t we let Rabban Gamliel serve us?”
The above laws refer to instances when a scholar is sighted in the public thoroughfare. The following laws apply when he enters the house of study (Hagahot Maimoniot; see Horiot 13b).

At present, when we are used to auditoriums with fixed seats, the setting for this law is difficult to picture. However, in Talmudic times, the people would sit on the floor. When the av beit din arrived, the people sitting between the entrance and his place would stand and create a path for him two rows wide.

On the surface, it is difficult to understand why the av beit din is given lesser honor in the house of study than in the marketplace. Perhaps the reason is to minimize the neglect of Torah study. Horiot 13b relates that, originally, the people would show the same token of respect to the av beit din and other sages as to the nasi. In order to preserve the authority of his office, Rabbi Shimon ben Gamliel, the nasi, ordained that a lesser degree of respect be shown to all other sages.

The house of study, a path is not made for him.

Avodat HaMelech notes that this figure is not found in Horiot 13b, the source for this law. Rather, it was added by the Rambam, based on the logic that no less respect should be paid to a scholar when he enters the house of study than is paid to him in the marketplace.

And allow him to pass.

I.e., there are many students whose presence is an invaluable asset to their teacher, for through their questions they enable their teacher to penetrate to the core of the subject matter. Therefore, they are allowed to proceed to their places at the front of the house of study, even if doing so is somewhat discourteous to the people who have already taken places.

Indeed, Berachot 43b lists this as one of six undesirable tendencies that a scholar should guard himself against acquiring.

Doing so is considered an act of laziness, which causes unnecessary difficulty to the people sitting there.

I.e., to use the toilet (Horiot loc. cit.). Alternatively, the term לצורך can be translated as “for a necessary purpose” — i.e., for a purpose that benefits the people at large (Tosafot, Yevamot 105b).

However, if he leaves for other reasons, he should try not to return to his original place.

Are not mature enough to merit a distinguished position in the house of study in their own right are allowed to sit before their parents as a gesture of respect to the high communal position the latter have attained (Rashi, Horiot 13b).

Horiot (ibid.) states that the children are allowed this privilege only during their father’s lifetime, but not afterwards.

Avodat HaMelech notes that the latter word is the Rambam’s addition to this teaching quoted from Kiddushin 33b. The addition implies that this restriction applies only to those students who are constantly in attendance at the house of study. In contrast, those who come from time to time must stand as often as necessary. (See also Tosafot, Kiddushin, ibid.)

In the house of study. In contrast, if a student sees his teacher in the marketplace, he is obligated to show him respect at every opportunity, lest others consider him to be disrespectful to his teacher (Kessef Mishneh).

Tosafot (loc. cit.) notes that the expression אינו רשאי can be rendered “is not obligated,” and suggests that meaning in this context. However, since rising more frequently can be construed to be an affront to God, it is questionable whether that interpretation can be accepted.

I.e., twice daily we accept the yoke of God’s service by reciting the Shema (Kessef Mishneh).

The Shulchan Aruch (Yoreh De’ah 244:1) explains this as referring to a man of seventy. Others, emphasizing that the Rambam uses the term “exceedingly advanced age,” see that as a reference to Gittin 28a, which describes a person ninety years old with such terminology.

The Rama (Yoreh De’ah 244:1) emphasizes that there is no obligation to stand before a wicked man. The commentaries have raised questions concerning this law, noting that it reflects a difference of opinion between two Talmudic sages, and yet the Rambam’s statements do not conform exactly to either position. Kiddushin 32b states:
“Stand up before a white-haired [man].” Does this apply even with regard to a
common person of advanced age? The Torah continues [mentioning] “an elder.” [The
term] “elder” refers only to a wise man, as implied by [Numbers 11:16]: “Assemble seventy of Israel’s elders.”
Rabbi Yosse HaGalili states: [The word] “elder” means “one who has acquired
wisdom...”
Issi ben Yehudah states: “Stand up before a white-haired [man]” — Every white-haired man is
included therein.
The Talmud explains that although the first opinion is similar to that of Rabbi Yosse HaGalili, there are minor differences between them. From the Rambam’s statements in Halachah 1, it would appear that he follows Rabbi Yosse HaGalili’s position. However, this halachah appears to echo Issi ben Yehudah’s view.

However, anyone other than a scholar is obligated to rise to his full height (Tur, Yoreh De’ah, 244).

Kiddushin 33a relates that Rabbi Yochanan would stand in deference to an aged gentile, explaining: “How many experiences has he gone through!”

Kiddushin (ibid.) notes that Rabbah would follow this practice.

Kiddushin (ibid.) notes that Abbaye would follow this practice.

The commentaries question: If, in fact, the verse refers even to gentiles, and Rabbi Yochanan would follow such a practice, why doesn’t the Rambam obligate standing in the presence of an aged gentile?

However, the scholars must bear their share of the cost of such projects (Hilchot Shechenim 6:6). The Shulchan Aruch (Yoreh De’ah 243:1-2) adds that they are obligated to pay only the cost of the raw materials. They need not hire workers to take their place. This applies only when the work is performed by the members of the community. However, if workers are hired by the community to complete the task, the scholars must also pay their share.

In Hilchot Shechenim (6:6-7), the Rambam gives some examples of such projects: fixing roads and thoroughfares and digging irrigation channels.

Bava Batra 8a explains that if the common people see the scholars performing menial tasks, they might cease to respect them.

In Hilchot Shechenim (loc. cit.), the Rambam explains the rationale for this law. Torah scholars are freed from any obligation incurred to ensure the city’s protection, because they are protected by the merit of their study.

The order in which this law is taught is somewhat questionable. Bava Batra 8a, the source for these laws, mentions a scholar’s lack of obligation to contribute to a present for the king as part of his absolution from taxes, and not as a leniency granted to him because “his Torah protects him.”

Bava Batra (ibid.) also mentions that Artashta, the Persian king who sent Ezra to rebuild Jerusalem, freed all those involved in this holy work from all forms of taxes and tribute. (See Ezra 7:24.) The Rama (Yoreh De’ah 243:2) states that even if the gentile government levies taxes on a Torah scholar, the community is obligated to pay the tax on his behalf. The commentaries question whether there are scholars today who are worthy of these benefits. The Shulchan Aruch (Yoreh De’ah 243:2) explains that these privileges should be extended only to those scholars who devote the majority of their time to Torah study and limit their business involvement to the minimum necessary to earn a livelihood. Other authorities have voiced other opinions, some stricter and some more lenient. (See Siftei Cohen, Yoreh De’ah 243:7; Choshen Mishpat 163:14.)

יתנו, translated as “will give,” can also be interpreted as “study,” alluding to the verse’s connection with scholars.

An allusion to the payment of taxes.

An allusion to the scholars’ exemption.

Rav Kapach notes that in the original, there is no vav before the word שרים. However, the quotation of the verse in Bava Batra (loc. cit.) does include one.

Although the Rambam harshly forbade a Torah scholar from taking money from charity because of his knowledge (see Chapter 1, Halachah 7 and Chapter 3, Halachah 10), he allows a scholar these privileges in earning his livelihood. The Shulchan Aruch (Yoreh De’ah 243:4) states that this law applies only when the market is controlled by Jews. However, if there are gentiles who will sell their goods regardless, the other Jewish merchants are not obligated to risk suffering a loss.

I.e., a case to be tried at court.

Sh’vuot 30a relates:
Rav Ullah, the son of Rav Ilai, was involved in a judgment before Rav Nachman.
Rav Yosef sent [Rav Nachman a message:] “Ullah is our colleague in Torah and
mitzvot.”
Rav Nachman said: “Why did he send this [notice] to me? To curry favor before
me.” Afterwards, he said: “[His purpose was] so that I try his case first.”
Tosafot questions this teaching, noting that there is a positive commandment to try every case in the order that it comes before the court. Two resolutions are offered:
a) If both cases come to the court at the same time, the court should try the case of the scholar first;
b) The positive commandment to honor a scholar overrides this positive commandment. Hence, the scholar’s case is tried first, even if it came before the court later. The Tur and the Shulchan Aruch (Choshen Mishpat 15:1) accept the latter position. (See also Hilchot Sanhedrin 21:6.)

Sh’vuot (loc. cit.) states: “’And the two men shall stand’ (Deuteronomy 19:17): it is a mitzvah for the litigants to stand.” Nevertheless, as a token of respect for the scholar, he is invited to sit. The same privilege is also granted to the litigant opposing him, because otherwise, this gesture would be considered to be an unfair advantage granted to the scholar.

Sanhedrin 99b equates such sinners with epikorsim — total unbelievers.

Shabbat 119b. This refers to the destruction of the city by the Babylonians.

Although the teaching is quoted from the Talmud, the Talmud does not itself define which of the verse’s clauses refers to the disgrace heaped upon the scholars. It is interesting to note that the Rambam’s interpretation differs from that of Rashi — who equates the Sages with “His prophets” — and of the Maharsha, who interprets “the messengers of God” as the reference to the Sages. (See also Guide for the Perplexed, Vol. II, Chapter 42 and Lechem Mishneh.)

Which precedes the list of curses to befall the Jews.

See Sifra, Bechukotai.

In Hilchot Teshuvah 3:14, the Rambam mentions the sin of disgracing the scholars in a list of transgressions concerning which he writes: “a person who frequently commits these sins will not receive a portion in the world to come.”

I.e., even though, as stated in the previous halachah, a person who disgraces a scholar will receive the ultimate punishment after his death, he is also subject to punishment in this world.

The Siftei Cohen, Yoreh De’ah 334:96, states that proper witnesses are not required, and even the testimony of women or slaves may be accepted.

The details of this ban are discussed in the following chapter — in particular, in Halachah 4 there. An example of a scholar placing individuals under such a ban for embarrassing a scholar can be found in Mo’ed Katan 16a.

The Beit Yosef, Yoreh De’ah 243, cites an example of the public announcement of such a ban from Kiddushin 70a. However, the section he quotes is not mentioned in our text of the Talmud.

A Talmudic measure equal to approximately 168 grams.

Hilchot Chovel UMazik 3:5-6 relates:
One who embarrasses a scholar is obligated to pay him the full extent of the damages
even though he embarrassed him only verbally. The decision has already been
rendered that whoever embarrasses a scholar — even with words alone — is fined..
eight and three quarter sela’im of gold.
It is an accepted tradition that this fine is collected everywhere, whether in Eretz
Yisrael or in the Diaspora. Decisions of this nature were frequently rendered before
us in Spain. Some scholars would forgo payment, and that is commendable. Others
would demand payment, but accept a compromise. However, the judges would tell
the person who caused the embarrassment: “you are obligated to give him a litra of
gold.”
The Rama (Yoreh De’ah 243:7) states that, at present, there are no scholars whose stature is that great that they are to be awarded “a litra of gold,” if they are publicly shamed. However, a person who embarrasses a scholar is obligated to pay damages. This is the general opinion of most authorities at present. However, in the generations before the Rama — and in certain communities, even after his decision — this fine was, in fact, imposed if someone publicly embarrassed a scholar.

The use of this term implies that this is a lesser transgression than embarrassing a scholar in his lifetime (Rivash, Responsum 120).

Eduyot 5:6 relates that the court imposed such a ban when someone made disparaging remarks about the scholars Shemayah and Avtalion. (See also Berachot 19a.)

The Kessef Mishneh notes that the Rambam’s statements appears to imply that the ban is not lifted until the offender actually appeases the scholar. He questions that decision, since it is possible that even though the offender genuinely asks for forgiveness, the scholar will refuse to grant it. Note Hilchot De’ot 6:6 and Hilchot Teshuvah 2:10, which advise a person who has been wronged to be generous and forgive the offender for his actions.

Acting on his own initiative, without bringing the matter to a court.

The Kessef Mishneh states that this expression implies that although a scholar can be placed under ban for embarrassing a scholar of greater stature, that ban may not be issued by the scholar alone, and can be put into effect only by a Rabbinic court. Nevertheless, he postulates that if the scholar who was embarrassed is of far greater stature than the scholar who made the insult, the former is allowed to issue the ban himself, without a court.

See Kiddushin 70a.

The Rama (Yoreh De’ah 243:8) mentions a difference of opinion whether, at present, there are scholars of the stature that allows them to issue a ban of ostracism without taking the matter to court. See also Pitchei Teshuvah 243:7.

I.e., the ban may be imposed without following the standard judicial process.

Even individuals who are not scholars worthy of sitting on a Rabbinic court (Chapter 7, Halachah 7).

The Rambam does not require the offender to ask forgiveness from the scholar (see Hilchot Teshuvah 2:11) or repent. Perhaps this leniency is granted because the ban was imposed by the scholar himself and not by an objective court.

If the scholar was publicly disgraced, disciplinary action must be taken, or else the honor of the Torah would suffer.

The Mishneh LeMelech notes that this leniency is granted only regarding matters between man and man. If a person is obligated to be placed under a ban of ostracism for matters between man and God — e.g., uttering God’s name in vain — the ban must be put into effect even though the individual repents. (See also Tosafot, Yevamot 22b.)

I.e., the case was not tried in court, but the teacher issued the ban of ostracism on his own initiative, as mentioned in the previous halachah.

For they are obligated to protect his honor. The Beit Yosef (Yoreh De’ah 334) maintains that one can infer from the Rambam’s words that the ban need not be observed by the other scholars, even those of lesser stature than the teacher, who are not his students.

For he is not obligated to honor his student to this extent.

Of a lesser Torah stature (Beit Yosef, Yoreh De’ah 334)

As mentioned in the following halachah, this applies only when the student imposed the ban to protect his honor. If he imposed the ban because the person violated a prohibition, his teacher would be obligated to observe it.

Whom all Israel are obligated to honor. This law is also quoted by the Shulchan Aruch, Yoreh De’ah 334:21. Note the commentary on Halachah 6, which questions the applicability of the term nasi within the context of our present-day experience.

Even an esteemed scholar.

For he is not obligated to honor others to this degree. In this case as well, were the ban imposed for other reasons, the nasi would be bound by it.

The Beit Yosef and the Rama (Yoreh De’ah 334:20) maintain that even a city whose Torah stature exceeds that of the city which issued the ban is obligated to abide by it.

Because he treated them disrespectfully.

But other cities of lesser Torah stature are required to observe it (Rama, ibid.).

Leniency that frees certain people from abiding by the requirements of the ban of ostracism

The Hagahot Maimoniot notes that a ban can be imposed only because of disrespectful behavior. However, this punishment may not be administered for failing to honor the scholar.

Many commentaries have noted the difficulty in the Rambam’s words. This statement implies that there is a certain leniency with regard to a ban imposed because of the embarrassment of a Torah scholar. However, the first of the 24 reasons the Rambam lists for imposing a ban of ostracism that must be observed by every Jew is disgracing a Torah scholar, implying that it is the most severe (see Avodat Hamelech). Among the resolutions of the difficulty offered is that there is a difference between a ban imposed by a court according to Torah law and a ban issued by a scholar individually to protect his own honor.

Mo’ed Katan 17a relates that Rabbi Yehudah HaNasi’s maidservant declared a ban of ostracism on a person, and the entire Jewish people observed that ban for three years.

See Chapter 7, Halachah 7.

Most of the instances where the Talmud mentions a ban of ostracism concern men. However, a number of cases (see Rosh HaShanah 31b, Mo’ed Katan 16b, and Nedarim 7b and 50b) also involve women.

Berachot 19a mentions that this is the number of reasons for which a person can be placed under ban, but explains only several of these twenty-four reasons. A significant number of reasons are also mentioned in the Jerusalem Talmud (Mo’ed Katan 3:1); however, the majority of the reasons mentioned by the Rambam below were gathered by him from many different passages throughout the Talmud.

Berachot 19a relates that a ban was imposed on a person for disgracing the scholars Shemayah and Avtalion, even after their passing.

Kiddushin 70b relates that Rav would impose a ban of ostracism for this reason.

See Kiddushin 28a.

See Bava Kama 112b and also Hilchot Sanhedrin 25:8.

Eduyot 5:6 relates that Eliezer ben Chanoch was placed under ban for raising difficulties regarding the practice of washing one’s hands, a Rabbinic ordinance.

The Kessef Mishneh notes that the Rambam uses the expression, “treats with disrespect.” If a person transgresses a command, he is punished by other means. However, ostracism is imposed for causing others to view a Torah or Rabbinic law disparagingly.

Bava Kama 113a serves as the source for this law. Note the slight difference between the Rambam’s statements here and those in Hilchot Sanhedrin loc. cit.

This concept, with these two examples, is quoted from Bava Kama 15b.

Bava Kama 112a mentions this point. Tosafot postulates that this restriction applies only when a Jewish colleague is prepared to pay the same amount as the gentile. However, if the gentile offers more than the Jew, the owner is not liable to sustain the loss. However, in Hilchot Shechenim 12:7, where the Rambam quotes this law, he does not make such a provision. Furthermore, in several of his responsa, he forbids selling property that borders on the property of a fellow Jew to a gentile, even when substantial losses are involved (Rav Kapach).

See Bava Kama 113b. In Hilchot Sanhedrin 26:7, the Rambam writes:
Whoever has his case judged by gentile judges and courts... is wicked and is considered as if
he cursed... the Torah of Moses.... If gentiles rule his society and his fellow litigant is strong-
willed, and it is thus impossible to collect [one’s due] from him according to Jewish law, he
should call him to a Jewish court first. If he refuses to come, he should receive the court’s
permission to preserve his property through secular law

But not a priest who slaughters for his personal use (Hilchot Bikkurim 9:8)

The foreleg, jaw, and the maw, which must be given to a priest from every animal slaughtered. (See Deuteronomy 18:3; Hilchot Bikkurim, Chapter 9.)

Chulin 132b.

See Pesachim 52a.

The Or Sameach explains that the Rambam added this clause because he had already stated that a person who disgraces a Rabbinic ordinance is liable to be banned. Hence, he clarifies that, at present, since we use a fixed calendar, the observance of the second day of the festivals is no longer considered to be a Rabbinic decree and is only a custom. (See Hilchot Sh’vitat Yom Tov 6:14.)

Pesach eve is singled out because the Paschal sacrifice was offered at that time. (See Pesachim 50b; Hilchot Sh’vitat Yom Tov 8:17.)

See Nedarim 7b; Hilchot Sh’vuot 12:9.

This is derived from the Jerusalem Talmud (Mo’ed Katan 3:1), which quotes how, in a time of drought, Choni HaM’agel drew a circle on the ground and called out to God: “I will not move from here until You provide rain.”
Shimon ben Shetach told Choni that his act warranted ostracism, because if God had not answered his prayers, many of the people would have lost faith. Nevertheless, Shimon ben Shetach did not enforce that punishment after he saw how God answered Choni’s prayers.

Berachot 19a relates how Todus of Rome instituted the custom of roasting lambs on Pesach eve in a manner similar to the Paschal sacrifice. The sages told him that, were it not for his other personal virtues, he would have been placed under ban, for it is possible that someone would actually consider his lamb as a Paschal sacrifice.

Berachot 63a relates that Isaiah 2:3: “Out of Zion will come forth the Torah...” implies that the above decisions must be made in Eretz Yisrael, and prescribes this punishment for someone who makes them in the Diaspora.

Note the commentaries to Leviticus 19:14 and also Sefer HaChinuch (mitzvah 232).

Mo’ed Katan 17a relates that Rabbi Yehudah HaNasi’s maidservant issued a ban of ostracism on a father who physically beat his son after the latter had reached adulthood. By doing so, he was goading his son into rebelling against his father. This ban was respected by all the scholars.

See the Jerusalem Talmud, Mo’ed Kattan 3:1. See also Hilchot Teshuvah 4:1.

The Kessef Mishneh quotes Sanhedrin 25a as teaching that Rav Nachman administered such a punishment. However, in our texts of the Talmud, that passage does not mention ostracism specifically.

See Chullin 18a. In Hilchot Shechitah 1:26, the Rambam states that this halachah applies even if later the knife was inspected and found to be kosher. The Kessef Mishneh notes that leniency is taken in this matter, because it has become customary for ritual slaughter to be performed only by experts. (See Tur, Yoreh De’ah 18.)

Niddah 13b; for by doing so, he leads himself to immodest thoughts, at the very least. (See also Hilchot Issurei Bi’ah 21:18.)

After divorce, a couple should have as little contact with each other as possible, lest the familiarity they previously enjoyed lead them to intimacy outside the bounds of marriage. (See also Hilchot Issurei Bi’ah 21:27.)

Mo’ed Katan 17a relates how Rabbi Yehudah passed a ban of ostracism on a sage for this reason.

Mo’ed Katan 17a relates the following episode: Resh Lakish was employed as a watchman and noticed a thief. Although he shouted at him, the thief did not stop. Therefore, Resh Lakish proclaimed: “You are under a ban of ostracism.”
The thief replied: “Although I am obligated to repay him, I am not obligated to be ostracized. You should be ostracized.” When the matter was related in the House of Study, the scholars stated that Resh Lakish’s ban was not justified, but the thief’s was.
The Ra’avad and other commentators mention other acts in which a ban of ostracism is in order. Indeed, in a number of cases (e.g., Hilchot Gerushin 13:20), the Rambam himself mentions this punishment. The commentaries explain that the Rambam limits himself to 24 instances, because that is the figure mentioned in the Talmud. However, these can be considered to be general categories including other instances as well.