“Rabbi Yishmael says: we seek Torah with thirteen middot.” (Torat Kohanim, introduction)
From whence do these middot derive? Are they halakhot leMoshe miSinai? Are they derabanan? If yes, what are the ramifications? Or are they something in between?
Ramban (Sefer haMitzvot, shoresh 2) insists that all the middot are halakhot leMoshe miSinai, as do Rashi and R. Shimshon of Kinon. However, the Ra’avad writes that at least two middot are not halakhot leMoshe miSinai. Instead, from the fact that the Torah sometimes employed the middah of kal vaChomer, we learn that we, too, are entitled to employ kal vaChomers. And from the fact that the Torah sometimes proffers two contradictory verses and then resolves them, we learn that we, too, may suggest resolutions to contradictory verses.
More radical than both Ramban and Ra’avad is the Rambam. Rambam writes that “whether laws derived via middot are true or not,” such laws cannot count on the list of 613 mitzvot. R. Eliyahu Elfandari (cited in Sha’arei haMiddot, pp. 20-21) suggests that Rambam is not challenging the middot’s divine origin. Rather, he is noting that the middot could be misapplied to derive incorrect halakhah from the written Torah. However, Ramban seems to interpret the Rambam’s comments as entertaining the possibility that none of the middot originated as halakhot leMoshe miSinai.
Rambam also writes that any law derived via the middot is only rabbinic. Obviously, Rambam does not mean that such laws are not punished on the biblical level. The power of a ring, when given from man to woman, to seal a marriage is only derived via a middah. Yet nobody maintains that the punishment for infidelity to such a marriage is any less than the punishment for infidelity to a fully biblical marriage. Rather, Rambam means that this law was not explicitly communicated by God to the Jews, neither through the written Torah nor through the oral Torah. The law was communicated only implicitly, and we only know of its existence because the rabbis deciphered it. Hence, it is termed “rabbinic.”
Rav Nissim Gaon (Eiruvin 2a) takes these atypical definitions of “biblical” and “rabbinic” even further. The concepts of eiruv – that one may not carry from individually-held domains to partnership-held domains and vice versa, but that if one creates an eiruv, one may carry thus – are described by the Talmud as “rabbinic.” Rav Nissim Gaon writes that in truth, they are “biblical,” since they were enacted into law prior to the time when the written Torah was canonized. Rav Nissim Gaon understands that a law is “biblical” if it originated early enough. Indeed, Rambam himself alludes to some authorities who understand that if Moshe Rabbeinu, or the legislature in Moshe Rabbeinu’s lifetime, passed a law, that law would be “biblical.” Nonetheless, the Talmud describes the concepts of eiruv as “rabbinic,” because if not for the tradition of the rabbis, we would never have known of their existence.
The aforementioned usages of “biblical” and “rabbinic” seem to be exclusively historical, and seem to have little relevance to halakhah. “Biblical” laws that originated before the written Torah was canonized would still be treated as leniently as laws that originated later, and “rabbinic” laws that were transmitted from Sinai or derived from the text of the written Torah would still be treated as stringently as laws explicitly stated in the written Torah.
However, Ramban (shoresh 1) argues that if one had to choose between a “biblical” mitzvah and a “rabbinic” mitzvah, the biblical mitzvah takes precedence. For instance, minimizing animals’ pain is a biblical mitzvah, while handling muktzah on Shabbat is a rabbinic prohibition; hence, one may sometimes handle muktzah to minimize animals’ pain. Along similar lines, Rabbi Eli Genack argues that a mitzvah on the list of 613 takes precedence to a mitzvah not counted on that list. Similarly, Rambam might maintain that when faced with a choice between an explicit mitzvah and an implicit one, or a mitzvah with earlier origins versus a later mitzvah, that the earlier and more explicit mitzvah takes precedence. In a sense, “biblical” and “rabbinic” are not purely historical terms, but rather are relative halakhic terms: “biblical” means “more proximate to explicit revelation,” while “rabbinic” means “more distant from explicit revelation,” where proximity and distance are halakhic factors that help us determine, when two mitzvos conflict with one another, which mitzvah we should perform first.