From the Rabbi’s Desk: Shabbos Scales

Question:

Dear Rabbi Sprung,

I have Type 1 diabetes, and I am meticulous about the amount of carbohydrates that I consume at each meal and use a scale to weigh my portions. During the week I use a digital scale but I know that it is forbidden to use it on Shabbos. May I use a mechanical scale without a digital display or electronic components?

Answer:

Shalom u’Bracha,

First of all, you are to be commended for taking care of your health in an exemplary manner. While Type 1 diabetes is a serious condition, you can manage it effectively by following a balanced diet, adhering to medical guidelines, and getting timely medical treatment. Doing so can avoid the most unpleasant and potentially dangerous symptoms, allowing you to live a full and balanced life like anyone else. This is particularly important for you as a young man just starting in adult life. By establishing good habits now, you will be blessed with good health for many years to come, God willing.

Regarding your question, you are correct that there is generally an Issur to use any form of measuring tool on Shabbos. However, in your case, using a digital scale is permissible. I will summarize the relevant Halachos; they are relevant to your question, weighing newly-born babies, using a thermometer, and many other common scenarios.

According to Rashi (Beitza 29a), the Issur of Medida (measuring) on Shabbos is due to it being Uvdin d’Chol (a weekday-type activity). Measuring instruments are usually used for Mekach u’Memkar (commerce).

Nevertheless, the Mishna in Shabbos details several exceptions (157a):

One may annul vows on Shabbos and request [of a Chacham] to release vows for the purpose of Shabbos. One may seal a window, measure a rag, and measure a Mikva. There was an incident in the time of R’ Tzadok’s father and the time of Abba Shaul ben Batnis, in which they sealed a window using an earthenware vessel and tied an earthenware shard with a long reed grass to ascertain whether the roofing had an opening the size of a handbreadth. We derived from their statements that one may seal a window, measure, and tie a knot on Shabbos.

The Gemara recounts the following, related episode (157b):

Ulla happened to be at the home of the Reish Galusa. He saw Raba bar Rav Huna sitting in a barrel of water and measuring it. Ulla said to him: “Perhaps the Sages only spoke about measuring for a Mitzva. Who said they spoke about [measuring that is] not for a Mitzva?” Raba bar R’ Huna replied: “I am simply ‘Misasek (I have no purpose in mind)’”.

In other words, measuring for a Mitzva – “Medida shel Mitzva” – is permissible on Shabbos. Why is this the case? In the case of other Issurim d’Rabbanan, the Chachamim made no exception for “Tzorech Mitzva”. Tosfos answer that since the Issur of Medida is merely due to Uvdin d’Chol, Chazal were willing to permit it l’Tzorech Mitzva, but they did not do so in the case of Issurim d’Rabbanan.

The Rambam has a different approach and holds that Medida is forbidden as a Gezeira lest one become involved in Mekach u’Memkar (Hilchos Yom Tov, 4:19-22):

Our Sages forbade many activities on Yom Tov as a decree lest people become involved in commerce… When they divide [the meat], they should not weigh it on a scale, for a scale should not be used at all… An experienced butcher may not weigh meat by hand. Nor may one weigh [meat] using a container filled with water… Similarly, a person should not take a [specific] measure or weight [of goods] from a storekeeper. What should he do instead? He should tell the storekeeper, “Fill this container for me,” and he should pay him for its value on the following day. Even if it is a container that is used for measuring, he may fill it, provided he does not mention any [specific] measure.

It follows that according to the Rambam, the Gemara’s allowance for Tzorech Mitzva is a much broader principle than simply a leniency for Issurim of Uvdin d’Chol. He states this explicitly in Hilchos Shabbos (24:5): “All of these, and anything similar, are a Mitzva, and the Posuk states, ‘To conduct your affairs’ – your affairs are forbidden, [but] the affairs of Heaven are permitted.”

Until this point, we have been discussing Tzorech Mitzva. What about Tzorech Refua?

The Shulchan Aruch rules (O.C. 306:7) that one may measure the belt of a sick person (and whisper incantations over it –a method of Refua, in earlier times) because it is a Medida Shel Mitzva. The source of the Mechaber’s ruling is the Tur, who cites two reasons for this Halacha:

It is permissible to measure for a Mitzva on Shabbos, such as measuring whether a Mikva contains 40 Se’ah and the like. Regarding an incantation that they whisper for a headache, where they take the patient’s belt, measure out three Amos’ worth three times, and recite the incantation while measuring it; the Avi Ezri (202) permitted this. There is no issue of uttering an incantation as this is permissible on Shabbos. Regarding the measuring – that is also no concern, as the measuring is only Misasek. R’ Moshe haKohen forbade it. The Maharam m’Rothenburg (quoted by the Tashbetz Katan 58) compared it to Medida Shel Mitzva.

According to the Avi Ezri, measuring a patient’s girth is only permissible because it is Misasek. In other words, it is an unnecessary and meaningless component of the medical “procedure”. (This is likely comparable to the act of Misasek of Raba bar R’ Huna, above). However, if this would not be the case – i.e., if there would be a non-incidental purpose for measuring – it would be forbidden. By contrast, according to the Maharam m’Rothenburg who permitted it because of Medida shel Mitzva, it would be permissible in all cases. The Shulchan Aruch accepts this latter reasoning.

The Elya Raba explains (21) that the point of dispute between the Avi Ezri and Maharam m’Rothenberg is whether measuring for the sake of Refua is considered part of the act of Refua or not. If it is part of the Refua, it can be permitted as a Mitzva. If not, it can only be permitted if it is Misasek.

The Shulchan Aruch‘s ruling is the basis for the Heter to take a patient’s temperature on Shabbos, even if his life is not endangered (Shulchan Aruch ibid. and Mishna Berura 36; Igros Moshe, O.C. 1:128, Meorei Eish 2:3:4; Shulchan Shlomo Erkei Refua 2, p142).^[1]

The same logic would apply to your case. Diabetes is considered at least an illness sheEin Bo Sakana, and often can reach the level of Yesh Bo Sakana. Some Poskim classify diabetes as a “Maka shel Chalal (an internal injury)”, which is always deemed a Sakana (see Shulchan Aruch O.C. 328) due to pancreatic dysfunction. In addition, there are life-threatening risks of extreme fluctuations in blood sugar, underscoring the importance of precise measurement of carbohydrate intake. Therefore, weighing your food is unquestionably permissible. If the only scale available is digital or electronic, you should consult a Rav for guidance. This is true even according to those who hold that weighing on Shabbos is stricter than other forms of measurement.

[1] We have previously discussed (Vayakhel 5784) whether a person who is not a Choleh may take his temperature on Shabbos. The Minchas Yitzchak forbids it (3:142 and 10:31). The Tzitz Eliezer (11:38) and Shevet haLevi (1;61) discuss whether a woman who is experiencing infertility may take her temperature on Shabbos to determine when she is ovulating. The Shevet haLevi considers this Medida shel Mitzva. However, this is not a straightforward position. Further discussion is beyond the scope of this essay.