A Time to Mourn: Aveilut as Minor Holiday

Ben Greenfield

Ed. note: this essay won Hadar’s annual Ateret Zvi Prize in Hiddushei Torah.

I. Introduction
Aveilut (the laws of grief and mourning) has no obvious home in the body of Halakhah.^[1] Consider, for example, the Mishnah’s six topical orders, and contemplate if any serve as an obvious host for a discussion of mourning. The options are Kodshim (Temple rites), Zeraim (agricultural law), Nezikin (torts and civil code), Nashim (nuptials and divorce), Taharot (ritual purity and impurity), and Moed (holidays). A satisfying choice remains elusive. It’s a shame that “none of the above” is not the Mishnah’s seventh order.

Ensuing authors of comprehensive halakhic works faced the same awkward challenge. Rambam infamously placed his laws of aveilut in, of all places, his Book of Judges, a volume that sets out the political bodies of Jewish self-government.^[2] Tur (followed by Shulhan Arukh) composed his section on aveilut within Yoreh De’ah, best known for its intricate presentation of kashrut and niddah.^[3] Grief must go somewhere, after all.

Today, students of aveilut often think of it as a lifecycle topic. Imagine a sefer that begins with birth, milah, and customs around baby-naming; that proceeds to childhood education in mitzvot and halakhot relevant to marking bnei mitzvah; continues with a full treatment of courtship, weddings, and marital life; discusses illness and visiting the sick; and concludes with aveilut. Imagining such a volume is possible, yet studying one is not, as no classic project to organize Halakhah around lifecycle lines has yet to succeed.^[4] (This itself suggests how modern it is to conceive of mitzvot as a set of life cycle rituals.^[5])

While both contemporary students and medieval writers have struggled with where to place aveilut, Hazal felt no such qualms. Their decision when codifying the Mishnah was no accident or unsatisfying last resort, but a natural choice, reflective of Hazal’s unique approach to aveilut itself. They wrote aveilut as part of Seder Moed, within the tractate Moed Katan (“minor holiday”) that is otherwise devoted to the laws of Hol Ha-Moed. If you want Hazal’s most sustained discourse on mourning, you must make the somewhat counterintuitive journey to Moed Katan 3:5–9 or, in the Talmud, Moed Katan 19a–29a.^[6]

This essay attempts to explain why.

II. Aveilut as Moed: In Theory
Before opening up the sources, let’s open ourselves to the idea of Jewish mourning as fundamentally a calendar phenomenon – akin to Pesach, Purim, or Tisha be-Av. The basic structure of aveilut reflects it. Death and burial set off a precise timeline: a week of shiva mourning, a month of shloshim mourning, a year of grieving for a parent. One can observe the mitzvot of tefillin or kashrut without consulting a calendar. But in aveilut, calendar is core.

Aveilut is certainly not a “holiday” in the sense of joy and celebration. But it is a “holiday” in the sense of structured time, marked by clear start and end dates, which create a break from regular, workaday life. In shiva, daily labor is forbidden, replaced by a series of seasonally appropriate mitzvot that, if performed any other week, would be as bizarre and untimely as shaking lulav in the spring. The right “holiday” mitzvot at the right “holiday” time.

In fact, the very concept of shiva – mourning for seven days – hinges on this connection. Why specifically seven? The Talmud (Moed Katan 20a) provides a fascinating answer:

On what basis is mourning seven days? For it is written, “I shall turn your holidays into mourning” (Amos 8:10; the ability to replace holidays with mourning, described in this verse, suggests a similarity in their overall structure). That is, just as the holidays are seven days, so too mourning is seven days… Reish Lakish in the name of R. Yehuda HaNasi: On what basis is delayed mourning [when news of a death arrives from afar after much time] only one day? As it is written, “I shall turn your holidays into mourning,” and we find that Shavuot, which is called a chag (holiday), is but one day.

Shiva is seven days long because Pesach and Sukkot are seven days long. Shiva is sometimes one day long because Shavuot is one day long.

If we accept the Talmud’s basic conceit – that the anatomy of mourning ought to match the anatomy of holidays – more details of aveilut fall into place. The Jewish holidays prohibit or otherwise limit work, replacing our weekday errands with obligatory meals, special holiday foods, uncommon holiday dress, and regulations around shaving and haircuts. During shiva, workday labor is forbidden; one eats an obligatory mourner’s meal (seudat havra’ah) and by custom, numerous “special” foods associated with grief^[7]; dress is regulated through the torn garment and lack of laundered or new clothing; shaving and hair cuts are prohibited. Most Jewish holidays come with a ritualized preparatory period (the many mitzvot of Erev Pesach, the customs leading to Rosh Ha-Shanah and Yom Kippur, Ta’anit Esther before Purim, etc.). Similarly, shiva is preceded by the unique practices of aninut (the pre-burial period of shock), effectively a period of erev aveilut. We “sit” shiva in what is today a visibly low chair,^[8] and we also “sit” the other seven-day chagim: on Pesach a mitzvah to lean; and on Sukkot a mitzvah lei-sheiv^[9] ba-sukkah. Each of these holiday components are found in aveilut.

In a more experiential sense, most Jewish holidays are commemorative, pushing us to remember people and events from the past that we might otherwise forget. With regular workday life interrupted, family, friends, and neighbors gather to reconnect and commemorate together. Aveilut, for so many, mirrors this holiday experience. Aveilut means days set aside to remember and commemorate the life of the deceased, accompanied by loved ones who travel in for the “occasion” and in the presence of neighbors and friends.

Viewing aveilut as a branch of “holiday law” makes sense for the entire institution. We mark mourning just as we would any Jewish holiday. The recipes may be different (Sukkot and aveilut should certainly feel different) but the cookbook is the same. Or, in the volume that Tannaim edited, Sukkot and aveilut require different sections, but they belong together in Seder Moed.

III. Aveilut as Moed: In Text
The aveilut/Moed connection is surprisingly compelling. But how firmly did the authors of the Mishnah embrace the connection? What indicates, on the level of text, that Hazal actually considered mourning to be a kind of holiday?

A dive into the mishnayot reveals that Hazal were terrifically consistent in portraying aveilut through the lens of holidays. One might expect that basic elements of aveilut – like burial, funeral, shiva, shloshim, etc. – would appear in the Mishnah as part of addressing the straightforward question: “How should a person respond to a relative’s death?” But a quick scan reveals that while each of those halakhic institutions are discussed, it is towards answering a completely different and rather surprising question.

3.5: One who buries their dead three days before a regel (a pilgrimage holiday) – the Shiva decree^[10] is canceled for him. Eight days before a regel, the shloshim decree is canceled for him…
3.6: Rabban Gamliel said, Rosh Ha-Shanah and Yom Kippur are like a regel [in that they too cancel mourning] …
3.7: The Mourners’ Blessing is not said on a holiday, but they do make lines [for the mourners to walk between]
3.8: Women wail in unison [at a funeral] on a holiday, but may not clap …
3.9: On Rosh Hodesh, Hanukkah, and Purim, they wail in unison and clap but on none of these do they wail responsively.

Apparently, the Mishnah’s primary inquiry is not, “how to mourn” but rather, “how do holidays affect mourning?” (Or to put it more boldly: How do regular holidays interact with the mourning holiday?) Core concepts like shiva, shloshim, and funeral behavior are only introduced as a vehicle to better understand what happens when mourning and festivals collide.

From the very first line and in each of the five mishnayot, the topic of calendar conflict appears. Take particular note of Mishnah 3:7, which is the source of such well known practices as keri’ah (tearing one’s clothes), sitting on a low chair, and offering words of comfort to the mourners.^[11] The Mishnah introduces nine rituals in quick succession, but solely for the purpose of naming what cannot be done when aveilut conflicts with Hol Ha-Moed (intermediary days of a holiday).^[12] Only by discussing what we cannot do on Hol Ha-Moed does the Mishnah find a way to tell us, implicitly, what we must do at a typical shiva.^[13],[14]

One way to make sense of these organizational choices is to embrace that Hazal viewed aveilut as a holiday, just one with an unusual feature: it can “fall out” at any point of the year. (Shabbat is the only holiday pinned to a specific weekday; the rest are pinned to a specific month or date; mourning, as many know all too well, is never so predictable.^[15]) This makes mourning the sole moed capable of producing a holiday scheduling conflict. Yom Kippur will never fall out on Hanukkah (obviously); yet aveilut can. Seder Moed spends ten tractates introducing the full line of calendar-stable holidays. Only in the eleventh tractate^[16] is it ready to resolve one closing question: what happens if the calendar-floating holiday (aveilut) gets in the way?

Today, we typically encounter the laws of mourning detached from their original framing. We learn these rules in modern guidebooks dedicated solely to mourning or from the Shulhan Arukh, which places them alongside tzedakah (charity), excommunication, and visiting the ill. We thus forget that for the great Sages of old, aveilut was written, framed, and conceived of as one step in experiencing the Jewish holidays.

IV. Aveilut in Moed Katan: The Minor Holidays
Hazal treat aveilut as a holiday, to be studied as a sub-branch of holiday law. But why did they set aveilut in, of all places, Moed Katan? How is the mourning holiday related to Hol Ha-Moed?

It is tempting to note that both holidays are in some sense katan (small, minor). Hol Ha-Moed’s mitzvah responsibilities are minor relative to the heavier observances of Yom Tov, and aveilut is itself “small” in one remarkable way. Even if mourning is a holiday, it is a thoroughly personal holiday, commemorating an individual loss, and its obligations fall not on the entire Jewish nation, but one small family set. Perhaps Hol Ha-Moed and aveilut share this masekhet (tractate) because each is, in its own way, a Moed Katan.

Indeed, these two “small holidays” share one key diminution: a minor prohibition on labor. Shabbat demands a total cessation of melakhah (labor; any of the 39 creative processes) and Yom Tov (holiday) entails a comparable ban. Interestingly, Hol Ha-Moed and aveilut also carry a ban on melakhah, but limited to the colloquial sense of the word “labor.” Big chores, annoying burdens, replacing the bathroom tile, writing up the quarterly review, clocking in at the office – that’s prohibited on Hol Ha-Moed and during shiva.^[17] Tearing paper towels or operating a cell phone, though melakhah in the technical sense, remain fully permitted.^[18] Hol Ha-Moed and aveilut are thus related – each a Moed Katan – in the sense of sharing a minor ban on melakhah.

That said, nothing in the Mishnah’s legal content or rhetorical choices highlights any of the above connections, or indicates that the Tannaim labeled either holiday as katan. Though the title of their shared tractate is today Moed Katan, that phrase was likely unknown to Hazal. Early Mishnah manuscripts and many Rishonim employed a completely different title, Mashkin (Irrigate), based on the text’s opening words.^[19] Further, the Mishnah itself never mentions the aveilut prohibition on melakhah, leaving the Gemara to introduce it.^[20] If the Tannaim placed aveilut within Moed Katan because both are “small” holidays or have “minor” work prohibitions, they were intent on not letting the reader know.

However, there is a more profound and more thematically resonant reason why Hazal would interweave aveilut and Hol Ha-Moed – and this reason is encoded into the content and even poetry of the Mishnah text. To unlock the code, and thus attain a complete sense of Hazal’s unique understanding of mourning in Jewish law, a little background in the laws of Hol Ha-Moed is instructive.

V. A Law Made Profane
The Halakhot of Hol Ha-Moed are shockingly – almost comically – contingent. For example, strenuous work like irrigating a field is quite clearly “labor” and is forbidden on the holiday. And yet, if the field relies on such irrigation and a full week without labor would harm the crop, it becomes permitted (Moed Katan 1:1). A long day of repairing the driveway or weeding the fields easily violates Hol Ha-Moed prohibitions. But when it comes to repairing public streets, the communal need takes precedence; when rabbinical agents wish to inspect fields for forbidden seedlings, their public service outweighs the weeding ban (1:2). R. Eliezer b. Yaakov rules that watering seeds is too laborious to undertake on Hol Ha-Moed. But, if the seeds are particularly thirsty, then it is permitted (1:3). You cannot dig holes to trap pests on Hol Ha-Moed, but in an orchard – where ripe fruit is at stake – go ahead (1:4). Fixing a door is professional labor, which ought to be banned on the holiday. But if a broken door obstructs the holiday spirit, such repairs are fine (1:10). If something important comes up and interrupts your pre-holiday work at the olive press, you may re-start the task on Hol Ha-Moed (2:1). Concerned about thieves? Spend the day bringing your produce home. You obviously cannot sell your wares at market, but if you’re short on funds to spend on the festival, feel free to open shop (2:4). For every rule, there is a “but.”

Just imagine if we took this approach to the laws (even the Rabbinic laws) of Shabbat! To an observant person, the thought experiment borders on the absurd. You cannot go into work on Shabbat, unless you are really needed at the office. You cannot sell merchandise, unless it will help with purchasing wine for that day’s kiddush. You cannot carry on a suburban street without an eruv (enclosure), but rabbis serving the public interest can. One cannot mend a garment, unless their torn shirt dampens the Shabbos spirit. It is typical of halakhic thinking to offer detailed distinctions about what does and does not constitute work. But it is quite surprising to see those distinctions quickly fade when an extenuating circumstance – public projects, an agricultural setback, a broken door – enters the picture.

Yet that is the nature of the laws of Hol Ha-Moed: it is the code of extenuating circumstances. Over and over again, the Mishnah offers examples of when its own rules do not apply. Chapter three introduces additional Hol Ha-Moed restrictions with the same indulgent relationship to sudden human need. Namely, one is forbidden to shave^[21] or launder clothes on Hol Ha-Moed. Since it was then a professional activity, penmanship is likewise banned. And yet, mishnayot 3:1–3 are an uninterrupted list of all the diverse situations for which one can shave, launder, and write.^[22] If one was traveling abroad and arrived home without time to prepare before the holiday, a Hol Ha-Moed trim becomes permitted. One cannot write bills of debt on the holiday, but if the lender does not trust the borrower, then call in the scribes. With so many exceptions, it is common for fairly observant Jews to experience, in our day, almost no sense of restriction on Hol Ha-Moed. In the face of official rulings, real life needs “but” in.

To be clear, there is a ubiquitous role in the annals of Halakhah for emergencies and sakanot nefashot (threats to life). With rare exception, any prohibition or obligation (e.g. do not drive on Shabbat) backs away in the face of mortal danger (on Shabbat, do drive a woman in labor to the hospital). But the laws of Hol Ha-Moed extend a similar treatment to a wide range of medium-stakes needs and past-tense excuses. Here too, Hol Ha-Moed is not utterly unique. Factors like hefsed (monetary loss) and even tzaar (discomfort) also have a mitigating role in Halakhah. Mere tza’ar undoes the obligation to dwell in a Sukkah. But read through Masechet Sukkah and find but few lines devoted to this principle and zero effort to compile all the various situations in which tza’ar outweighs Sukkah. In every other realm of Halakhah, extenuating circumstances have to be written into the margins. For Hilkhot Hol Ha-Moed, they are the law itself.

VI. Aveilut All Along
Moed Katan, with its focus on Hol Ha-Moed, is the tractate of extenuating circumstances. It is there that the Mishnah addresses those moments in which a personal, real-life need actually trumps the rules. This is precisely why our Sages chose Moed Katan for their discussion of aveilut.

Grief remains – even in our time and culture – the extenuating circumstance par excellence. Persnickety professors acknowledge that a family death means an exam will be missed. Airline call-center bureaucrats issue bereavement refunds. Clients understand that if there was a death in the family, professional obligations will not be met. Note that mourning is not an “emergency” in anything like the pikuach nefesh sense. There is no crisis to resolve, no life to save, nothing left “to do.” And yet, in mourning, one is granted relief from the typical rules that regulate regular time.

It is this feature of mourning that the Tannaim highlight throughout their composition of Moed Katan. The aveilut section occurs only at the tractate’s end (3:5–9); yet grief is present all along. What constitutes a public need? Marking graves (1:2). Though chiseling tombs and crafting coffins is far too laborious for Hol Ha-Moed, an exception is made when a body lays before us (1:6). What is a valid excuse for why your olives are still stuck in the press, such that you justifiably need to work them during the holiday? A death occurred, and the obligations of mourning interrupted your original press time (2:1, 2). Most legal documents may not be written on Hol Ha-Moed. But an exception is made for a deathbed testament (3:3). Aveilut appears in Moed Katan because, from chapter one through chapter three, aveilut is a story of extenuating circumstances.

If you look closely, you’ll find this connection woven into the very poetry of the Mishnah. As a text, Moed Katan is built around a recurring key word: אבל. The term appears 15 times in the short tractate; echoing across all three chapters and marrying the first statement of the Mishnah with the last. אבל is a double entendre. Read one way, these three letters produce “but” (אֲבָל), as in: “the Halakhah is X, but in an extenuating circumstance, it is Y.” Vowelized differently, it means “mourning” (אֵבֶל). The poets of the Mishnah (who inherited an oral text, full of similarly handy memorization tools) jump between the two usages, inviting the reader to pause, in each case, and consider: does this instance of אבל signal a mitigating factor, an instance of mourning, or both?

Since mourning is the quintessential extenuating circumstance, it is natural for the Mishnah to ask just how far those exculpating powers extend. Can aveilut also suspend the obligations of Purim? Shavuot? Pesach? That question frames the entirety of the aveilut code (3:5–9) and creates a truly unified masekhet. Moed Katan opens with the holiday most susceptible to interference from extenuating circumstances (Hol Ha-Moed), and closes with the extenuating circumstance most likely to interfere with the holidays (aveilut).

VII. The End
Why did Hazal place aveilut in Seder Moed? Because they consider it a holiday practice. Aveilut is a calendar phenomenon, with specific start and end times. Its seven day structure is explicitly borrowed from other holidays; its work stoppage, obligatory meals, customary foods, special clothes, regulated sitting, and limitations on laundry and haircuts all accord with the festival paradigm. But as the only “holiday” without a set calendar date, aveilut forces us to consider what to do when one holiday conflicts with another. Only in answering that question in holiday law, does the Mishnah introduce the core teachings of Jewish mourning.

And why did Hazal specifically place aveilut in Moed Katan? Because they recognize Aveilut as the ultimate extenuating circumstance, and Moed Katan is the tractate devoted to the interplay of holidays and extenuating circumstance.

In a sense, holidays are themselves extenuating circumstances. Workweek life is an amalgam of professional duties, family responsibilities, and errands to be juggled. These obligations build to the point that one might mistake them for the totality of one’s life and identity. But in the observance of a holiday, we recognize that we are party to narratives and values beyond the prosaic – narratives which, when push comes to shove, trump the everyday. In Jewish holidays, the “regular world” continues its regular business, while we participate in an exceptional reality: the thrill of liberty from Egypt, the hilarious volte-face of Purim, the cosmic drama of Judgment Day. Something happened (or is happening) and I simply cannot come into work today.

Mourning is no different. Each person participates in narratives of love, loss, and transition whose depth neighbors and professional colleagues will never fully know. We pass through the collective calendar of recognized work days and shared recreational hours, while each carrying in our own hearts a private calendar of grief days and joyful seasons. In the institutions of aveilut (shiva, shloshim, the first year, yahrtzeits), Halakha recognizes the sanctity of that private calendar. Even if August 1 means nothing to the world at large, it means everything to me. You can go to work. I have to sit here. Something came up, and I will never be the same.

Jewish tradition gifted us two magnificent sets of structured time, in which to reflect on our most formative chapters. As members of an ongoing covenant, the national moadim are the scaffold for reifying who we are; as individuals with private lives and personal tragedies, the personal moed (aveilut) is the frame for revisiting whom we’ve lost. The brilliance of both is the transformation of a one-off, past experience into a continuing calendar of sacred time.

Yet, on the grand scale of covenantal time, even the holidays of the national calendar can be extenuated. The Sages of the Midrash knew that when a true revolution in human history arrives, the new consciousness it produces will render most of our festivals void. We will no longer need to step into the alternate reality of Passover freedom, when the glow of Messianic freedom pervades our everyday. “All moadim will in the future be canceled,” the Midrash proclaims.^[23] Since mourning is itself a holiday, it is no exception. The Mishnah of Moed Katan closes with the redemptive image of grief finally outshone. In the Mishnaic poetry, the aveil (mourner) will one day be “aval’ed” (“but”ed”):

אֲבָל לֶעָתִיד לָבֹא הוּא אוֹמֵר, בִּלַּע הַמָּוֶת לָנֶצַח, וּמָחָה ה’ אֱלֹהִים דִּמְעָה מֵעַל כָּל פָּנִים

But in the future, the verse reports, ‘God will swallow up Death forever, and the Lord will wipe away the tears from upon all faces’ (Isaiah 25:8).

Moed Katan’s last words evoke a world touched by Divine comfort, in which Death’s best efforts to harm our loved ones are finally to no avail.

^[1] I am deeply grateful to a number of friends, colleagues, congregants, family, and loved ones who reviewed drafts of this essay. Your edits and encouragement make my writing possible. Thank you.
Thank you to Bais Abraham Congregation, for with their support my pulpit rabbinate included a weekly Gemara shiur (lecture) for undergraduates at Washington University (St. Louis). I am grateful to the Greenpoint Shul, under whose aegis that shiur became the “UWS Chabura in Aveilut”, serving alumni and New York friends of the WashU community. It was in the context of preparing and teaching that habura (study group) that the seeds of this essay were first sown. A special thank you to the individual WashU students who organized those two spaces for Talmud Torah. I also offer thanks to the Hooper Street Satmar Shul, in whose vast Beit Midrash I conducted my learning and research for this paper. Finally, I am deeply grateful to Hadar for considering my work for this prize, and to the family of Prof. Szubin z”l for establishing this initiative. I hope that these words of Torah bring honor to his name.

^[2] Atypically for Rambam, he inserts into the heading to Hilkhot Aveil a brief justification of his choice: “… a person may not mourn over someone executed by the court; and for this reason did I include these laws [of mourning] within this Book [of Judges], for they embody burying [a person executed by the court] on the day of their death, which is a positive mitzvah.”
See Isador Twersky, Introduction to the Code of Maimonides, p. 286, who describes this explanation as “enigmatic and forced” and states that it is “the best illustration of Rambam’s troubled awareness of the challenges and obstacles” of neatly organizing all of Halakhah. See also Moshe Halbertal, Maimonides: Life and Times, who declares that Rambam’s justification “seems contrived” and dedicates a subchapter to the question.

^[3] Tur (R. Yaakov b. Asher) does not indicate to the reader a unifying theme for his Yoreh De’ah. Broadly speaking, Yoreh De’ah’s structure is borrowed from Rashba’s Torat Ha-Bayit, with Tur appending additional topics that were related or which had no better home elsewhere in his project. (Court procedure and civil code appear in his Hoshen Mishpat; mitzvot of the festival and daily calendar go in Orah Hayyim; issues of marriage and divorce appear in Even Ha-Ezer). As such, topics as diverse as kashrut, conversion, lending with interest, oaths, mikveh, mezuzah, and mourning all end up here.

^[4] R. Eliezer Melamed’s ongoing Peninei Halakhah contains an intriguing schema. It includes a volume dedicated to “Family,” which opens with the mitzvah of honoring parents, covers marriage and marital life, and closes with mourning.

^[5] Though Rambam, Tur, and now Peninei Halacha provide strikingly different homes for Aveilut, they share one common feature: aveilut is always at the end. In Yoreh De’ah, it occupies the concluding 64 sections of code. In the structure of family, it is the culminating topic. For Rambam, aveilut appears not just in the last of the Yad’s 14 exhaustive volumes, but as the penultimate topic in all of Halakhah (followed only by his eschatological section on kings and the Mashiah). As noted below (n. 16) this fits a pattern established by the Mishnah itself. Tur provides a striking reason for this in the introduction to Yoreh De’ah: “The Laws of Mourning – I shall conclude [Yoreh De’ah] with it for it is every person’s end.”

^[6] Here too, aveilut is placed at the very end, as 3:5–9 is the final section of the tractate, one which is itself quite late in Seder Moed. Moed Katan is the eleventh of Moed’s twelve tractates. This is the order as found in today’s printed Talmud Bavli and attested to by Rambam. This produces a nice symmetry in Rambam’s organizational choice. He placed aveilut as the penultimate topic in his ultimate volume, matching how Seder Moed puts aveilut as the ultimate topic in its penultimate volume. That said, Rashi and the Tosafot appear to have had a slightly different order of tractates, which is perpetuated today in the standard print of Talmud Yerushalmi. Here, Moed Katan is in fact the last of Seder Moed’s twelve tractates, and the mishnayot about mourning represent the seder’s very end.

^[7] Yoreh De’ah 378:1,9.

^[8] See Yoreh De’ah 387 for the original practice of kefiyat ha-mitah (overturning the bed) which is no longer observed, and for the remaining practice of sitting on the ground. See Arukh Ha-Shulhan Yoreh De’ah 387 for the evolution of these practices and why sitting on a low chair satisfies the mandate to sit on the ground.

^[9] Leisheiv ba’sukkah means to dwell in a Sukkah (a mitzvah that includes such actions as eating, sleeping, and lounging in the Sukkah) but it also has the more specific denotation of sitting in a Sukkah. In fact, Rambam (Sukkah 6:12) holds that one should recite the blessing of leisheiv ba’sukkah while standing, and sit immediately thereafter. Maggid Mishneh (ibid.) notes that, generally speaking, we make a blessing for a mitzvah immediately before performing it and infers that, according to Rambam, sitting is in some sense the core manner of performing this mitzvah. Either way, Pesach, Sukkot, and aveilut share unique mitzvot related to bodily position. There is regular year sitting, and there is the special holiday “sitting” of Pesach (leaning), Sukkot (in a Sukkah), and mourning (low chair).

^[10] The above rendering of gezeirat shloshim and gezeirat shiva (shloshim and shiva decree) follows the Steinsaltz translation. It reads “gezeirat” as the conjunctive form of gezeira, – decree, mandate, edict. Here, it would mean something like, “the halakhic mandate about shiva” or possibly “the Rabbinic edict about shiva”. (See Sukkah 12a for an example in this sense in the conjunctive form: gezeirat otzar  – “the Rabbinic edict against using a storehouse as a Sukkah”.) This fits well with the preceding term beteila, canceled or nullified, a word that appears in the context of legal decrees. That said, while gezeirain the sense of halakhic mandate is ubiquitous in the Gemara, this would be its only instance in the Mishnah.
As an alternative rendering, I wonder if  gezeirat could be taken as the conjunctive form of gezeira – form, structure. The Mishnah would be talking about the “structure of shiva” and the “structure of shloshim”. That seems to me to be a more natural phrase than “the shiva decree” and “the shloshim decree”. While not perfect precedents, see Lam 4:7 for the term gezeira in regard to the shape or cut of a precious stone and see Ezekiel 41–42 for examples indicating an architectural structure.

^[11] The full list is: tearing keri’ah, baring shoulders, eating a seudat havra’a (post-funeral meal), sitting on overturned beds, sending food to the mourners in plain baskets, reciting the Mourners’ Blessing, forming lines to greet the mourners, comforting the mourners, and dismissing the comforters.

^[12] This follows the dominant view that every line in this Mishnah addresses the unique case of mourning on Hol Ha-Moed. It is the approach taken by Rambam (Commentary to the Mishnah, Hilkhot Yom Tov 6:23, Hilkhot Aveil 11:2-3) Rosh (Moed Katan 3:58), Ramban (Moed Katan 24b), Raavad (cited by Rosh), Raavya (cited by Rosh), Bartenura, Yachin, et al.
However, the view of Ritva (who also cites the Rash m’Shantz) is that only the last four teachings specifically address Hol Ha-Moed. In this read, the opening lines of the Mishnah have nothing to do with Hol Ha-Moed and introduce mourning rituals as they would be practiced year round. Ritva would agree that four (but not nine) key rituals are introduced to us solely through the lens of how to navigate a conflict with Hol Ha-Moed. Shulhan Arukh rules in accord with the former interpretation (Orah Hayyim 547:6–9), which I here follow.

^[13] The fifth teaching in this Mishnah – to send food in plain baskets – is unique in that even if it was stated in regard to Hol Ha-Moed, all agree that the rule applies with the same force year round. (Cf. Rambam, Aveil 13:7). The Mishnah introduces this teaching not to imply that fancy baskets are typically permitted, but to reinforce that even at a festive time like Hol Ha-Moed ostentatious packaging must be avoided. (Cf. Ramban, Yakhin, Tosafot Yom Tov). What is the issue with elaborate baskets? The Gemara (27a) explains that wealthy neighbors would send food in gilded containers, causing poor comforters shame at their own relatively paltry offerings. In response, the Sages instituted that all comforters – wealthy or poor – deliver food only in plain baskets.

^[14] There is another, more subtle, sign of Hazal’s tendency to discuss aveilut within the context of holiday law. As many sHolars have pointed out, certain mishnayot contain allusions to what appear to be early, pre-Mishnaic Rabbinic teachings. Such allusions provide a window into which halakhic questions were worthy of early Rabbinic attention and which answers were widespread enough to merit reference in the Mishnah itself. [One well known example is Pesahim 1:1, which states “And what did they mean when they said [that one must check for hametz] in two rows of the cellar?” Somebody reading this Mishnah might fairly wonder who this “they” is that ever said such a thing and when “they” ever said it. Apparently, there was an earlier rabbinic statement about two cellar rows, which the editors of the Mishnah assumed readers of the Mishnah would already be familiar with. See Tosafot R. Akiva Eiger ibid., which claims that there was a huge corpus of early, pre-Mishnaic texts, and that this line in Pesahim clearly alludes to one such teaching. For an in-depth discussion, see Mordechai Sabbato, “Lama Amru Shtei Shurot be-Marteif?”]
Moed Katan 3:5–9 seems to contain an allusion to one such “early” teaching: “One who buries their dead three days before a regel (pilgrimage holiday) – the shiva decree is canceled for him. Eight days before a regel, the shloshim decree is canceled for him, as they already said, “Shabbat counts as a day of shiva and does not interrupt it; the regalim do interrupt shiva but do not count for it.” The “as they already said” introduces an early teaching that predates and serves as the legal basis for the Mishnah’s opening teaching. This early teaching has a neat, polished form, with a clear A/B/B/A rhetorical structure; the Hebrew would be easy to memorize and transmit, and carries the timbre of a popular catchphrase. But note that this “early” teaching on aveilut is not about mourning per se, but is about holiday conflict. We thus find yet one more way in which the Tannaim consistently treat mourning as a sub-branch of holiday law. What appears to be the earliest teaching addresses not the question of how to mourn, but how to navigate the interaction of holidays and mourning.

^[15] The view of the beiytusim, a prominent Jewish sect in the time of the second Beit HaMikdash, was that Shavuot always falls on Sunday. This position was stridently rejected by the Sages. See Menahot 10:3, Menachot 65a.

^[16] Some count Moed Katan as the twelfth and final tractate in Seder Moed. See n. 5, above.

^[17] See Yoreh De’ah 380 for the melakhah ban for mourners and Orah Hayyim 533-545 for the melakhah ban on Hol Ha-Moed.

^[18] See Hagigah 18a, and the range of Rishonim there, for the precise nature of the Hol Ha-Moed work ban.

^[19] Some knew the tractate as Moed, with the Katan” added to help contrast the masekhet named Moed from the much larger seder named Moed. In this light, it would be incorrect to infer from the name Moed Katan that the holidays discussed therein are in some sense “minor.” It is the text, not the holidays, that is small. (Much as the fairly small Midrashic collection Ruth Zuta – Little Ruth – has a title which speaks to the size of the text, not the nature of its protagonist.)

^[20] For example: “These are the matters which a mourner is forbidden to engage in: they are forbidden to do melacha …” (Moed Katan 21a); “A mourner in their first three days is forbidden to do melakhah” (21b). See also Moed Katan 11b, which explores the parallel between the Hol Ha-Moed prohibition and the aveilut prohibition on melakhah.

^[21] The prohibition on shaving includes a ban on haircuts.

^[22] This list of Hol Ha-Moed leniencies is yet another bridge between Hol Ha-Moed and mourning. Tosefta Moed Katan 2:1–2 states: “Anyone for whom they said that they can shave on Hol Ha-Moed is likewise permitted to take haircuts during the 30 days of mourning … Anyone for whom they said that they can do laundry on Hol Ha-Moed is likewise permitted to launder during the 30 days of mourning.” See Moed Katan 14ab and 17b for the Gemara’s references to this teaching. Interestingly, the Mishnah – unlike the Tosefta – fails to highlight this connection, despite it being a perfect bridge between the rules of Hol Ha-Moed (3:1–4) and the code of mourning (3:5–9).

^[23] Midrash Mishlei 9:1, Yalkut Shimoni Nakh 944. Interestingly, Purim will persist. Rashba (Responsa 1:91) walks back the radical nature of this midrashic teaching. For a discussion of certain sacred texts being “canceled” in the future, see Yerushalmi Megilla 1:5 and Rambam, Megilla ve-Chanukah 2:18.