Siman שמ"ד · 2 Seifim
A first approach to Siman שמ"ד: the full Hebrew text of the Mechaber, a clear English translation, pedagogical explanations of the halachic concepts, modern practical cases, and a synthesis.
Subject: Lost in the midbar — when does Shabbos begin?
Source: שולחן ערוך אורח חיים סימן שמ"ד (2 seifim)
Compiled by: רב יוסף חיים סממה
DAAT · daattorah.com
📑 Study outline
1. The text of the Shulchan Aruch
Siman שמ"ד contains 2 seifim of the Mechaber (Rav Yosef Karo) that codify the halachos of din haholech bamidbar b'Shabbos.
Seif א
דין ההולך במדבר בשבת. ובו ב סעיפים:
ההולך במדבר ואינו יודע מתי הוא שבת מונה שבעה ימים מיום שנתן אל לבו שכחתו ומקדש השביעי בקידוש והבדלה ואם יש לו ממה להתפרנס אסור לו לעשות מלאכה כלל עד שיכלה מה שיש לו ואז יעשה מלאכה בכל יום אפילו ביום שמקדש בו כדי פרנסתו מצומצמת ומותר לילך בו בכל יום אפי' ביום שמקדש בו:
Seif ב
היה יודע מנין יום שיצא בו כגון שיודע שהיום יום רביעי או יום חמישי ליציאתו אבל אינו יודע באיזו יום יצא מותר לעשות מלאכה כל מה שירצה ביום שמיני ליציאתו שביום כזה יצא מביתו דבודאי לא יצא בשבת וכן ביום ט"ו וביום כ"ב וכן לעולם:
2. The general context
What is this siman about?
Siman שמ"ד deals with an extreme but conceptually rich case: a person lost in the midbar who has lost track of the days and no longer knows when Shabbos falls. How does one keep Shabbos when one does not know which day it is? The siman applies the halachah to a situation of total doubt about the calendar.
Place within Hilchos Shabbos
Siman שמ"ד closes a small series of simanim dealing with situations of distress and doubt (traveler, midbar). It illustrates a key principle: doubt does not nullify the mitzvah — it reorganizes it. The source is in the Gemara (Shabbos 69b), a famous discussion.
3. The key halachic concepts
Four concepts structure this siman:
- שָׁכַח / סָפֵק — total forgetting of the calendar: one no longer knows which day is Shabbos.
- מוֹנֶה שִׁבְעָה — counting seven days from the moment of awareness, and keeping the seventh as Shabbos.
- קִדּוּשׁ וְהַבְדָּלָה — being mekadesh the seventh day, "so that Toras Shabbos not be forgotten."
- כְּדֵי פַּרְנָסָתוֹ — strict sustenance: one works the minimum needed each day, since survival takes precedence over a Shabbos of doubt.
- יוֹם הַיְצִיאָה — the day of departure: if he knows it, he can identify days that are certainly not Shabbos (8th, 15th, 22nd…).
4. The seifim in detail — one by one
Seif א — The traveler who has forgotten everything
One who no longer knows at all which day is Shabbos counts seven days from when he became aware of the forgetting, and keeps the seventh with kiddush and havdalah. A decisive distinction based on his provisions:
| Situation | Conduct | Reason |
|---|---|---|
| He has provisions | No melachah, no day, until they run out | As long as he survives, the safek Shabbos is respected |
| Provisions gone | He works each day the strict minimal sustenance — even the "sanctified" 7th day | Pikuach nefesh: survival takes precedence over an uncertain Shabbos |
| Walking (traveling) | Permitted every day, even the 7th | Ordinary walking is not a melachah |
Seif ב — The traveler who knows his departure day
If he knows how many days have elapsed since departure (without knowing the weekday on which he left), he can reason: he surely did not set out on Shabbos. So the 8th day since departure corresponds to the same weekday as departure — a certain weekday. Likewise the 15th, the 22nd, etc. On those days he may work freely.
5. The Mishnah Berurah — opening entries
The Mishnah Berurah of Rav Yisrael Meir Kagan (the Chafetz Chaim) has 11 entries on this siman. Here are the opening ones — to better understand the pshat of the seifim:
For the full text of the entries, see Sefaria: Mishnah Berurah 344.
6. The position of the Rama
The Rama adds no hagahah to this siman: the Mechaber and the Rama agree here, and the halachah is unified for Sephardim and Ashkenazim alike. It is mainly the Acharonim — Mishnah Berurah, Pri Megadim — who spell out the practical details.
- The case also applies to a captive among non-Jews who has lost track of the days (Yerushalmi).
- The day of becoming aware itself counts as the 1st of the six days.
- If he has neither bread nor wine for kiddush, he fulfills it through the Shabbos tefillah (and havdalah through atah chonantanu).
- Chabad → follow the Shulchan Aruch HaRav, siman שמ"ד (see Level 4).
7. Modern practical cases
The "midbar" case seems rare, but its principle — keeping Shabbos amid doubt of the calendar — has very concrete applications:
| Situation | Quick analysis |
|---|---|
| Prolonged travel / isolation (the open sea, an expedition, a long hospitalization with loss of time) | If one has lost track of the days: count seven days and be mekadesh the seventh. |
| Crossing the international date line | A distinct but related modern question; requires a specific rabbinic ruling. |
| Partial doubt (one knows the number of days elapsed since a certain marker) | Apply seif ב: identify days certainly not Shabbos (8th, 15th…). |
| Lack of means of sustenance | Survival takes precedence: minimal vital work permitted each day, even the "sanctified" day. |
8. Practical synthesis of the siman
- Doubt does not nullify Shabbos: one who has lost the calendar counts seven days and is mekadesh the seventh (kiddush, havdalah).
- Survival takes precedence: without provisions, one works each day the strict minimal sustenance — even the sanctified day.
- With provisions: no melachah, no day, until they run out.
- Ordinary walking is permitted every day.
- If one knows the count from departure: days 8, 15, 22… are certainly not Shabbos — free melachah.
- For the halachah l'maaseh, consult your local Rav.
9. Comprehension questions
- What is the general subject of Siman שמ"ד?
- How many seifim does this siman contain? What is the theme of each?
- What is the difference between the Mechaber and the Rama (if any)?
- Which structuring halachic concepts appear in this siman?
- What is the practical takeaway for daily life?
- In which borderline cases should one consult a Rav?
To go further
- 📚 Level 2 — Lamdan: for pilpul, the shitos of the Rishonim, fundamental chakiros, and the Acharonim's nuances
- ✨ Level 3 — Synthesis: for review and quick memorization with mnemonics
- 📜 Level 4 — Daat HaRav: the shitah of the Alter Rebbe (Shulchan Aruch HaRav siman שמ"ד)