A Shabbos Primer

Basic Concepts in the Melachos of Shabbos

Rabbi Shlomo Cohen  (originally prepared in the 70s)

Shabbos is a very special day. Over the millennia Jews have been known by dint of keeping Shabbos. During the Inquisition the church sent out instructions to be on the lookout for those homes in which smoke was not emanating from the chimneys on Saturdays.

Shabbos is one of the few Mitzvos in the Torah that is both a Kum V’Asay, a positive commandment, as well as a Lo Sa’Aseh, a negative commandment.

This treatment is nowhere near exhaustive. Anyone learning Masechta Shabbos or Hilchos Shabbos will require a working knowledge of these terms.

The difference between Melacha and Avodah

We have a Mesora from Moshe Rabbeinu that the 39 categories of labor are deduced from the types of activities necessary to build the Mishkan. Seforim describe a Machlokes regarding whether the Melachos are learned just from the activities necessary to build the Mishkan or does it include activities necessary for Korbonos as well.  Babli and Yerushalmi bring different sets of P’sukim from which we learn the 39 Avos Melachos.

In either case, only these 39 types of “work” are forbidden D’Orysa.

We may, therefor, carry a heavy load around the house the entire Shabbos, while walking outside with a pin is forbidden.

A Melacha may be defined as that which is the result of the use of intellect resulting in a change of state in an object from that which it was to something new. Carrying is the only exception to this definition.

Avodah, on the other hand, is an activity which may not result in a change of state.

Avos and Toldos

Although the 39 Melachos are deduced from the building of the Mishkan, they are not the only forbidden activities. Chazal have forbidden many that are similar in nature to the Avos Melachos. These are called Toldos. Among the differences between the two are the Korbonos one would have to bring.

Including Toldos, there are not 39, but hundreds of forbidden activities.

Meleches Machsheves

In order for an activity to be forbidden there must be a desire to accomplish this specific activity.


Some prior thought must be given to do a particular Melacha.

Davar She’eino Miskaven

When one does an activity on Shabbos, and a secondary prohibited result occurs, the secondary result is not an Aveirah.

For instance, we are forbidden to plow on Shabbos (Av). Similarly, we may not drag something across sand or dirt if we wish a furrow to result. Should we wish to move a bench across a room, with a dirt floor, we may do so as long as we have no intention of digging a furrow, and there is a possibility that a furrow won’t be dug.

Melacha She’eino Tzricha L’Gufa

When one does not need the result of a Melacha there is no Torah prohibition. There is, however a Rabbinic prohibition.

For example, if one digs a hole, which is forbidden, but does not need the hole, only the dirt from the hole, it is forbidden D’Rabbanan.


Grama is an indirect result of an action. Opening a frig door does cause the light to go on directly but does not automatically turn on the motor. There are several steps intervening between opening the door and the motor starting, in effect making this Gorem Grama, one indirect action causing a second indirect action resulting in the desired action.

K’L’Acher Yad – Sheenui

A Melacha D’orysa must be done in the manner it was accomplished in the Mishkan. If one employs some change in manner, the prohibition is then only Rabbinic.

Thus, if one needs to use a phone on Shabbos, one should preferably touch the keys with the left hand.


Since a Melacha is primarily a constructive activity, destruction (with a few obvious exceptions) may either be prohibited D’Rabbanan or completely permitted.

Thus, tearing a dirty Pamper off an infant is permitted.

Davar She’eino Miskayem

The Melachos of the Mishkan were done to have permanence, therefor, any activity which only lasts temporarily is only forbidden Rabbinically. (E.g. writing in the moisture on a window.)

Psik Reishei

Psik Reishei refers to an inevitable consequence of an action. The entire phrase literally means “cutting off its head won’t kill it?”, the original example is someone who wants to give his child a chicken head to play with on Shabbos. The problem is killing a chicken on Shabbos is forbidden.

Now, on Shabbos it is sometimes permitted to do an action that might have a forbidden consequence, if it is not one’s intent to cause the forbidden consequence. This is not the case with Psik Reishei. If you cut off the chicken’s head, the unintended consequence, the chicken’s death, is inevitable, and forbidden.

Psik Reishei D’Nicha Leih

Where one is satisfied with the resulting consequence

Psik Reishei D’lo Nicha Leih:

On Shabbos, where the resulting consequence is neither wanted nor intended, it is classified as a Psik Reisha D’lo Nicha Leih, which is permitted by Torah law but prohibited by Rabbinic law.

Psik Reishei D’Ichpis Leih

Where one cares about the resulting consequence

Psik Reishei D’lo Ichpis Leih

Where one does not care about the resulting consequence


If one knows that it is Shabbos, and deliberately does a Melacha, and there are two witnesses who gave warning one would be Ovair D’Orysa and be M’Chuyav Meisa..


On the other hand, if, either one does not know that it is Shabbos or is not aware that this activity is a Melacha, one would be Ovair, but would only be required to bring a Korbon Chatas.


Should one accidently do a Melacha, e.g. bump into the light switch, it is as if nothing happened.

Shas HaD’chak

In an emergency situation, where there is danger to life, there is a Machlokes Rishonim as to whether to treat Shabbos as Shabbos with certain Heteirim or as any other day of the week.


An Oneis is one who is forced by the situation to do a Melacha. Again, no harm, no foul.


The legal Latin term is a priori, up-front – to begin with.


The legal Latin tem is ex post facto, after the fact. In Halacha, the term is frequently used in permitting an otherwise less preferable activity.

Amira LAkum

Telling a non-Jew to do a Melacha on Shabbos is normally forbidden. Hinting to the non-Jew may be permitted.


Those activities forbidden by Rabbinical decree.

Tikkun Manneh

Fixing an object so that it now works. For instance, winding up a watch that has stopped. Also called Tikkun Kli. Both are related to the Av Melacha of Makeh B’Patish.

Uvda D’Chol

Any activity, normally reserved for weekday, should not be done n Shabbos. Likewise, a utensil that is normally used for a weekday activity should not be used on Shabbos. [e.g. mopping the floor}


There are six categories of Muktza:

  1. מוקצה מחמת חיסרון כיס –An item which is guarded due to value.[ A mohel’s knife]
  2. מוקצה מחמת מיאוס – Anything disgusting.[ vomit, feces]
  3. מוקצה מחמת גופו – Something which is forbidden by its very nature. [rocks, nails]
  4. כלי שמלאכתו לאיסור – A utensil used to do a forbidden Melacha. [colander]
  5. מוקצה מחמת מצוה – An article used for a Mitzva not done on Shabbos. [Lulav & Esrog]
  6. בסיס לדבר האיסור  – Any article on which something Muktza was resting when Shabbos began.[Leichter tray]


When something, which was not here during Bein HaSh’msasos, but was formed on Shabbos, it is Muktza. For example, an egg was laid on Shabbos.

HaChana Mei’Shabbos L’Chol

Making preparations for the weekday on Shabbos. [e.g. washing the dishes late Shabbos afternoon: dressing for a Motzei Shabbos date while it’s still Shabbos]

Sakanas Nifashos

When there is danger to the life of any Jew taking care of that person overrides Shabbos. In fact, there is a Machlokes Rishonim over whether one should treat the day as Shabbos with some Heterim or as Tuesday or Wednesday.

Sakanas Eiver

Where the danger is not to a person’s life, but they would stand a chance of losing a limb, some Shabbos restrictions are loosened but not as far as danger to life.

Shvisas B’hemto

We are commanded not only to cease our labor but that of our animals as well, thus, if one owns a cow or horse that animal cannot go out of an enclosed area wearing a halter or the like, nor may it be rented to a non-jew to use on Shabbos.


T’chum Shabbos refers to a circle with a diameter of two thousand Amos. An Amah is roughly either one and one-half to two feet making two thousand Amos between three thousand and four thousand feet. One may not travel beyond a point that far from the edge of town. Should another settlement start within that distance the T’chum would start on the other side of the second settlement.


Carrying is the 39th Melacha. The Melacha is broken into several categories

Reshus Ha’Rabbim

A Reshus HaRabbim refers to a public domain. This is defined as a place where more than 600,000 people pass in one day. Ocean Parkway in Brooklyn may satisfy this requirement.

Reshus HaYachid

Reshus HaYachid is any private property.


Carmelis is a Rabbinical construct. It is not a Reshus HaRabbim D’Orysa nor is it a Reshus HaYachid.

Makom Patur

A Makom Patur is an area that is four Amos above or below the surrounding area.

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