And the 66th mitzvah is that we are commanded to bring a peace-offering in the manner described in [the passage beginning with] G‑d's statement,1 "If one's sacrifice is a peace-offering..." The Torah completes the description [in the passage2] "This is the law of a peace-offering...if it is offered as a thanksgiving offering..."

These four mitzvos3 — the burnt-offering, sin-offering, guilt-offering, and peace-offering — encompass all the sacrifices, since every animal sacrificed by an individual or the congregation falls into one of these four categories. The guilt-offering, however, is only brought by an individual, as we have explained on many occasions.4

Tractate Zevachim describes the laws of these four mitzvos, and everything pertaining to them — what one is required to do [in order that the sacrifice be valid]; what one is punished for doing; what will invalidate the sacrifice; and what is considered a valid sacrifice.