shabbos candles

The Shabbos Weekly
Halachos Series on Hilchos Shabbos

shabbos candles

Published by
Pirchei Shoshanim

A Project of
The Shema Yisrael Torah Network

Based on the Shiurim Given by

Rabbi Dovid
Ostroff, shlita

developed from the Chabura of the
Pirchei Shoshanim Shulchan Aruch Learning Project

These Halachos were shown by Rabbi Ostroff to
HaGaon HaRav Moshe Sternbuch, shlita


Questions for the Week of Parshas Devarim

Is one permitted to measure for the sake of a mitzvah?

As mentioned in the last shiur, measuring on Shabbos is an issur d’rabanan because it is a weekday activity - 'ovda d'chol' . However, measuring for the sake of a mitzvah cannot be termed an 'ovda d'chol'  because it is done for the sake of a mitzvah. [1]

Do you have examples of such measuring?

If milk fell into a pot of chicken soup, in order to eat the soup it must be sixty times the volume of the milk. One may estimate the volume of the soup and pasken accordingly. [2]

  • A mikveh must hold a certain quantity of water: if there is doubt as to whether the mikveh contains sufficient water, one may measure the volume of water.
  • Another case deals with purity. The halacha is that impurity emanating from a dead body can pass through a gap in the wall if the gap measures a tefach by a tefach. It is sometimes necessary to measure this gap in order to know whether kohanim can remain in the room adjacent to the dead body. One may use a tape measure or ruler and measure the gap on Shabbos.
  • It is imperative that one make kiddush on a cup that holds a quarter of a lug of wine or grape juice. If one is in doubt as to whether the cup holds the required amount, one may measure it on Shabbos. A possible method is to use a baby’s bottle, which has the units written on it and fill the kiddush cup accordingly.
  • One must eat a required amount of matza and maror on Pesach night and in order to know the correct amount, one may measure with one’s hand or with any other measuring instrument.
  • One may not walk a distance of 2000 amos outside of the town’s perimeter. A practical way to measure on Shabbos would be to count one’s steps, obviously depending on whether one knows how large one’s steps are. Accordingly one may walk that distance while keeping track of how far one is walking from the town.

What about for the sake of a baby or for an ill person?

The Mechaber says [3] that one may measure for the sake of the ill because it is considered measuring for a mitzvah. The Mishna Berura explains [4] that healing is itself a mitzvah and therefore measuring is a part of the mitzvah.

  • One may measure the quantity needed for medicine. This is true for powder, tablets and liquid.
  • One may measure the amount of food and liquid required to be eaten on Yom Kippur in a case of pikuach nefesh. Often it suffices to eat a small amount without having to eat a full amount and one may measure this amount when necessary.

A baby or child is considered in halacha as having a weak system and therefore one may measure the amount of powder needed to be placed inside the baby’s bottle etc.

Why is “measuring time” not ossur (you look at your watch, don’t you)?

The question is better than the answer. It is because one is not really measuring anything, one is merely calculating a spiritual factor. One could debate whether taking one’s temperature is the same thing, but irrespective, one may take one’s temperature on Shabbos when illness is an issue. [5]

What about weighing oneself on Shabbos?

Unless there is a medical reason, it is forbidden to weigh oneself on Shabbos. We already mentioned that a baby or child is different and if they indeed need weighing after a meal for health reasons it is permitted.

What about looking at a barometer on Shabbos or at a room thermometer?

Here again we can say that one is not really measuring anything physical, or even doing an action of measuring, and thus one may look at them on Shabbos.

It is worthwhile knowing that if one uses a measuring tool such as a measuring spoon and one is not meticulous that the measure be accurate, it may be used. [6] One should remember this and implement it whenever one is in doubt, whether one is permitted to measure on Shabbos or not.

[1] See M”B 306:34.

[2] Many of the following examples can be found in the SS”K 29:38.

[3] Simon 306:7.

[4] Simon 306:36.

[5] SS”K 29:39.

[6] See the Rama in simon 323:1 and M”B 5.

Food For Thought

There is talk about buying a house on Shabbos in Eretz Yisrael, what exactly is permitted?

When is one permitted to violate the Shabbos in order to prevent a fellow Jew from doing a greater sin?

Answers coming next week.

Vort on the Parsha

People often say that if Hashem would reveal His might they would repent and keep the mitzvos, but until then…

Moshe Rabeinu points out to the People Of Israel (1:30) that “even though you saw great miracles in the desert and throughout the time you were with Hashem you saw that He controls everything, nevertheless you do not believe in Him fully”. Seeing is not enough, and if one does not continually work on strengthening one’s belief in Hashem, it does not have an everlasting effect on a person ('ta'am v'da'as').


For a printed version, click here.


One may receive and distribute these weekly shiurim by calling or writing: Office 99 Rechov Bayit Vegan, Yerushalayim,
Phone Numbers:U.S. and Canada 732-370-3344 Israel 972-3-616-6340
 South Africa 083-714-3166 England 44161-792-2492 Australia 61-296835626 Switzerland 01141430288
e-mail:, or, weekly sponsorships are available as well. 

If you would like to send a question to Rav Ostroff, you can write to him at

Note:  The purpose of this series is intended solely for the clarification of the topics discussed and not to render halachic decisions. It is intended to heighten everyone's awareness of important practical questions which do arise on this topic.  One must consult with a proper halachic authority in order to receive p'sak.