Reference for Makkot 27:3

ורבנן כרת באחותו למה לי לחלק וכדרבי יוחנן דאמר רבי יוחנן שאם עשאן כולם בהעלם אחד חייב על כל אחת ואחת

And why was kares repeated by [the prohibition of cohabiting with] his sister according to the Rabbis [Rebbi Yishmael and Rebbi Akiva]? To [teach us that sacrifices are] separated [with regards to bringing a sacrifice for an inadvertent offence], as Rebbi Yochanon said that if a person did all [of these kares prohibitions] in one lapse of unawareness he is liable [to bring a chatos sacrfifice] for each and every one of them.

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