Question
Rashi continually refers to “Toras Kohanim” as a source. This obviously is not Leviticus itself, nor is it Sifra. Where would I find this Toras kohanim?
Answer
Actually, your Sifra and Toras Kohanim are one in the same; Toras Kohanim (meaning ‘Laws of the Kohanim’) is just a more descriptive name for the Sifra. It is also (less commonly) called Sifra d’Vei Rav, since it was compiled by Rav in the second century CE, generally following the teachings of Rabbi Yehuda.
Shlomo Shulman
JAAM CT
Maimonides at Yale