Shabbos, Gavra or Cheftza? — Eruvin 55b
תלמוד בבלי מסכת עירובין דף נה/ב
אמר ליה רבא דגלי מדבר קאמרת כיון דכתיב בהו על פי ה' יחנו ועל פי ה' יסעו כמאן דקביע להו דמי
R' Yosef Engel (Asvan D'Orysa §10) cites a theory advanced by many Acharonim, that all prohibitions that are time-limited, such as the prohibition to perform melachah on Shabbos or Yom Tov, only pertain to the gavra — the person who performs the melachah, and not to the cheftza — the melachah is performed. Thus, for example, it is only if a Jew cooks that the Shabbos prohibition is violated and the food forbidden. However, if the food was cooked without the involvement of a Jew, the food would not be forbidden (at least not d'orysa).
Accordingly, writes R' Yosef Engel, one can answer the question posed by the Tosafos Yom Tov (Shabbos 7:2), why the melachos are described in the mishnah as "one who plants," and "one who harvests" (הזורע, הקוצר) etc. — why does it not just say "planting" and "harvesting" (זריעה, קצירה) etc.? If we accept, however, that it is not the cheftza of the melachah that is prohibited, but rather the gavra that is prohibited to do the melachah, we readily understand why the mishnah is written in this manner.
R' Yosef Engel cites evidence both for the possibility that Shabbos is a gavra prohibition and for the possibility that Shabbos is a cheftza prohibition. However, the entire issue is predicated on the assumption that Shabbos is a time-limited prohibition. This is not necessarily so.
The Shem MeShmuel (Chayei Sarah 5679) posits that the essential quality of Shabbos is Shevisah — cessation, which in this context means cessation of all mundane concern so as to focus on the will of Hashem. Moreover, as Rashi (Shemos 31:15) writes, Shabbos affords us a permanent, or lasting sense of tranquility (menuchas margo'a), not a temporary respite (menuchas aria).
Asks the Shem MeShmuel, isn't a Sukkah — which is in use for seven days — called a "temporary dwelling" (diras aria)? How then can Shabbos, which is only one day, be defined as permanent?
In answer, the Shem MeShmuel cites his father, the Avnei Nezer, who said that at the onset of every Shabbos all melachah becomes forbidden forever. It is only that through Motzoei Shabbos and Havdalah melachah is again permitted. The Shem MeShmuel likens this to our Gemara, in which Rava states that the construction in the Midbar was considered permanent because each encampment was permanent — it was only as a result of a new command from Hashem that they would leave one encampment and travel to another.
Thus, it is quite possible to define Shabbos not as a time-limited prohibition, but as a permanent prohibition that is (unfortunately) disrupted by Motzoei Shabbos.
May we be zocheh to experience the true permanence of Shabbos, when it will never be disrupted, yom she'kulo Shabbos u'menuchah l'chayei olamim.