The Torah states: “But the seventh day is Shabbat of the Lord your God; you shall not do any melakha” (Shemot 20:9). The Sages explain that the intent of this verse is to forbid all 39 melakhot that were instrumental in erecting the Mishkan. One of these melakhot is Hav’ara (kindling a fire), which was necessary to prepare dyes for the Mishkan’s curtains. Nevertheless, the Torah explicitly mentions the prohibition of Hav’ara: “You shall kindle no fire throughout your settlements on Shabbat” (Shemot 35:3). The Sages ask why it was necessary for the Torah to single out Hav’ara. R. Natan explains that the Torah was using one melakha to serve as an example, to teach us that while all 39 prohibited melakhot are derived from one verse (“You shall not do any melakha”), nevertheless each and every melakha is an independent prohibition. Therefore, if one unknowingly performs multiple melakhot, he must bring a sin offering for each one of them (Shabbat 70a).
The awesome power of fire allows man to rule over the forces of nature and harness them in his service. Through the use of fire, people created metal tools, improved food, and later created powerful machines. Perhaps this is why Hav’ara was chosen out of all the melakhot to express man’s tremendous ability to improve the world. However, on Shabbat every Jew must rest and rise above all creative activity. We must remember our Creator who took us out of Egypt, and we must enjoy Shabbat via Torah study and festive meals.
At first glance, there is a basic question about the melakha of Hav’ara. We have a ruling: “All destructive acts are exempt [by Torah law, but liable rabbinically]” (Shabbat 105b). Therefore, if one tore an item of clothing or broke a utensil, he is not obligated to bring a sin offering. To be sure, he transgresses rabbinically, but not by Torah law. In light of this, and given that burning an item generally ruins it, why is lighting a fire on Shabbat considered a transgression of a Torah prohibition? The answer is that any time the positive elements provided by the fire (heating or lighting one’s home) outweigh the loss of the burned item, it is classified as a constructive rather than a destructive act (MT 12:1; see Kesef Mishneh).