Special Halacha delivered by HaGaon Rav Shemuel Pinhasi Shelit"a of Jerusalem
The Gemara in Masechet Yoma cites a debate between Rabbi Yohanan and Resh Lakish concerning the issue of "Hasi Shiur" ("partial quantity"), meaning, the case of a person who eats less than a Ke’zayit of forbidden food. It is clear that a person who eats a Ke’zayit of forbidden food, such as Nebela (meat from an animal that had not undergone Halachic slaughtering), is liable to corporal punishment (assuming there were witnesses who warned him before he committed the act). If a person eats less than this amount of Nebela, however, he is not liable to court-administered punishment. Resh Lakish understood this distinction as indicating that the Torah does not forbid eating less than a Ke’zayit of forbidden food at all. Rabbi Yohanan, by contrast, maintained that the Torah forbids eating any amount of Nebela or other forbidden foods. Even though one who eats less than a Ke’zayit is not liable to Malkot (lashes), he nevertheless transgresses a Torah prohibition.
The Rambam (Rabbi Moshe Maimonides, Spain-Egypt, 1135-1204), follows Rabbi Yohanan’s position, and this is, indeed, the accepted view.
The question arises as to whether this concept applies as well to the prohibitions of Shabbat. For example, a person is not liable to punishment for separating foods on Shabbat (Borer) unless he separates a certain amount. If he separates less than this amount, has he transgressed a Torah prohibition? Do we say that here, too, the Torah forbids any amount, even though punishment is warranted only for a specific quantity, just as we say with regard to forbidden foods?
Rashi (Rabbi Shlomo Yitzhaki of Troyes, France, 1040-1105), in Masechet Shabbat (74), writes that the concept of "Hasi Shiur" applies to the Shabbat prohibitions, just as it applies to eating forbidden foods. The Hacham Sevi (Rabbi Tzvi Hersh Ashkenazi, Amsterdam, 1660-1718) disagreed, and held that this concept is restricted to the area of forbidden foods. Thus, for example, according to the Hacham Sevi, one who has in his possession less than a Ke’zayit of Hametz on Pesah does not transgress the prohibition of "Bal Yera’eh U’bal Yimaseh" (owning Hametz). Many authorities followed Rashi’s position and maintained that the concept of "Hasi Shiur" applies to all Torah prohibitions, and not only to the area of forbidden foods.
One might, at first glance, challenge this view in light of the explicit Halacha allowing one to carry an object on Shabbat in a public domain for a distance of less than four Amot (cubits). Seemingly, this proves that the principle of "Hasi Shiur" does not apply to the Shabbat prohibitions, as in this case, one performs a partial forbidden act – carrying an object two or three Amot, instead of four. (Similarly, one is allowed to lift an object in a private domain and bring it into the public domain without putting it down there, and vice versa.) How can we reconcile this Halacha with the position of many authorities that the law of "Hasi Shiur" applies even to the prohibitions of Shabbat?
The answer, as noted by several scholars (including the Maharitz Hayot and Korban Netanel), lies in the distinction between two concepts – "Hasi Shiur" and "Hasi Melacha." "Hasi Shiur," as discussed, means a partial quantity of a certain substance. The case of carrying for a distance of less than four Amot is a situation of "Hasi Melacha," or half an action. The Torah prohibited the act of carrying a certain distance in a public domain on Shabbat, and therefore, one who carried for a shorter distance has not acted against the Torah’s command. This is much different than the case of eating a half-Ke’zayit of Nebela, where the individual ate something defined as forbidden, albeit not in a quantity that renders him liable to punishment. In the case of carrying on Shabbat a distance less than four Amot, the individual did not commit any forbidden act, and therefore has not violated Shabbat.
This distinction resolves a question raised by the Mishna Berura (Rav Yisrael Meir Kagan of Radin, 1839-1933) relevant to this issue. The Mishna Berura noted that Rabbenu Yeruham (France-Spain, 1280-1350) followed Rashi’s view, that the principle of "Hasi Shiur" applies to the Shabbat prohibitions. Yet, Rabbenu Yeruham elsewhere ruled that one who writes only one letter on Shabbat does not violate a Torah prohibition. Seemingly, the Mishna Berura notes, Rabbenu Yerucham’s rulings are contradictory. Writing only one letter seems to fall under the category of "Hasi Shiur," as the person has done only half of what constitutes a Melacha (forbidden action) on Shabbat. Why, then, does Rabbenu Yerucham not consider this a Torah violation?
The answer, I believe, lies in the aforementioned distinction between "Hasi Shiur" and "Hasi Melacha." The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909), in his work Shenot Eliyahu (a collection of transcribed discourses which he presented on his father’s yahrtzeit), analyzes the Halacha which exempts one from punishment if he writes only one letter. He raises the question of whether the writing of two letters is required as the minimum "Shiur" (quantity) of written content, or if the action of writing with respect to Shabbat is defined as writing two letters. He concludes that the Melacha of writing is defined as writing two letters, such that writing a single letter does not constitute a forbidden activity at all. Accordingly, we easily understand why Rabbenu Yerucham felt that writing a single letter does not constitute a Torah prohibition. Even though he maintains that the concept of "Hasi Shiur" applies to Shabbat, writing a single letter is a case of "Hasi Melacha," and performing half a Melacha does not violate a Torah prohibition.
