Binyan Av-Establishment of a Model

There is a concept in Halacha known as בנין אב. This is translated as “establishment of a model,” or a “paradigm,” or a type of “precedent.”

This means that a specific law in the Torah is chosen as the example that will apply in similar situations. This principle is given as the explanation as to why the kindling of a fire on Shabbat is prohibited. This particular law is placed in a different Parsha, Vayakhel, when the source for all Shabbat prohibitions is in the previous Parsha, Ki Tissa.

The Talmud in Masechet Shabbat teaches that the Melacha of kindling a fire was chosen to teach that just like it is listed as one of the primary prohibitions, known as Av Melacha, and one is liable for it alone, the same is true for the other thirty-eight Melachot that they are judged by themselves.

The implication is that if one knew that it was Shabbat and he inadvertently violated two separate Melachot, such as kindling a fire and cooking, he would need to offer two separate sin offerings, for each separate Melacha that was transgressed.

This rule was learned by way of Binyan Av from the specific prohibition of not kindling a fire on Shabbat.