It is forbidden for a Jew to work on Shabbat. What is the esoteric reason for this prohibition?

It is important to understand that working on Shabbat implies on a “decree of death” (Shemot 31:15), chaz v’shalom. The Sod or mystical aspect of this subject is extraordinary, and I shall reveal only a small degree while hiding much more, merely summarizing in a simple form, all based on the Kabbalah of the Ari”zal (Sefer HaLikutim, Parashat Behar, et. al.). Although it is not ideal to reveal such things to such unprepared recipients, here follows my kavanah, may the Heavens witness this, to help those that still have any doubts regarding the prohibitions of work on Shabbat, so they may quickly do teshuvah and receive the kabbalat ol. As the Talmud says, “the person should do teshuvah one day before his death, e since we do not know when is this day, it is vital do be always doing teshuvah” (alluding to Shabbat 153a).

During the regular weekdays, there are spiritual forces that descend to our world’s level of reality in order to allow that tikkunim (“rectifications”) be made into effect through the permitted works to a Jew. In a more specific manner, every permitted work done during the week serves, in a way or another, to raise netzuzin kedoshim (“Divine sparks”) fallen in the physical level when the order of reality was not our current order of rectification, the Olam HaTikkun, but rather, the preceding order of the Olam HaTohu (“World of Chaos”). The order of the Olam HaTohu was broken apart, so to speak, through a deep and fundamental process of the Divine plan for the revelation and  ultimate evolution of Creation, particularly man, as it is taught by the Ari”zal. These spiritual forces that are the vehicle, through which all of these spark-elevations occur, return to their spiritual degree and level on Shabbat. On Shabbat, all is new, signifying that there is no need for spiritually elevate anything that has fallen from the destroyed primordial world of Tohu. Hence, there is no need for tikkunim on Shabbat. All is in order, truly perfect on Shabbat. Not even the work of boreh (“separation of food”) is allowed, for separating that which is not good in the food from the good part in it of itself implies in a removal of a negative element from a positive one, and that does not exist on Shabbat when after all, everything is in the category of the desired and rectified. Now, when the Jew performs a melachah (“forbidden work”) on Shabbat, chaz v’shalom, he elicits these spiritual forces that normally should operate only on weekdays to descend to the physical world in order to make into effect the appropriate spark-elevations.

However, as nothing can be elevated on Shabbat, these forces become as ‘forces in vain’, chaz v’shalom. Through this, the klipot, the negative forces that block the revelation of Divinity in the material world, can steal these spiritual powers, this holy light, and make use of them for its own negative uses, chaz v’shalom. Moreover, the klipot are called the “power of death”, and when the Jew profanes the Shabbat through some forbidden work, he receives the celestial decree of punishment through death, chaz v’shalom, since, worse than not using these forces for the elevation of fallen sparks, is the fact that they may fall under the domain and “clutches” of the klipot. This has the effect of literally nourish the klipot and sitra achra, the person then becoming a “partner of evil”, may Hashem have mercy on his soul. This nourishment has the additional effect of blocking the benefiting purpose of the Or Ayin Sof, thus causing a diminution of spiritual shefa (“flux of blessings”) to the world at large. This has the further effect of causing severe decrees (in the form of afflictions) to befall the person (and those close to him) who performed the transgression, the community, and the whole world, chaz v’shalom.