And the 69th mitzvah is that we are commanded that one who unintentionally transgressed any one of the serious, well-known1 prohibitions must bring a sin-offering.

The source of this commandment is G‑d's statement2 (exalted be He), "If any person commits an inadvertent violation."

This is the "fixed sin-offering" [chatos kavua], since it is always an animal.3

The details of this mitzvah are explained in tractate Horayos4 and Kerisus,5 and in several places in Shabbos,6 Shavuos,7 and Zevachim.