Shevuot 2B

על הטהור שאכל את הטמא.

They atone for a ritually pure person who unwittingly partook of ritually impure sacrificial food.

רבי מאיר אומר: כל השעירין כפרתן שוה, על טומאת מקדש וקדשיו.

R' Meir says: With regard to all the goats offered as additional offerings, those of the New Moons, Festivals, and Yom Kippur, their atonement, i.e., the atonement that they effect, is the same; they all atone for the defiling of the Temple by entering it while impure, or for the defiling of its sacrificial foods by partaking of them while impure.

היה רבי שמעון אומר: שעירי ראשי חדשים מכפרים על הטהור שאכל את הטמא, ושל רגלים מכפרין על שאין בה ידיעה לא בתחלה ולא בסוף, ושל יום הכפורים מכפר על שאין בה ידיעה בתחלה אבל יש בה ידיעה בסוף.

R' Shimon would say, delineating his opinion as the Mishnah expresses it above: The goats of the New Moons atone for a ritually pure person who unwittingly partook of ritually impure sacrificial food. And with regard to the defiling of the Temple or its sacrificial foods, the goats of the Festivals atone for cases in which one did not have awareness, neither at the beginning nor at the end, and the goats of the additional offerings of Yom Kippur atone for cases in which one did not have awareness at the beginning but did have awareness at the end.

אמרו לו: מהו שיקרבו זה בזה? אמר להן: יקרבו. אמרו לו: הואיל ואין כפרתן שוה, היאך קרבין זה בזה? אמר להם: כולן באין לכפר על טומאת מקדש וקדשיו.

The Rabbis said to him: What is the halakha with regard to whether goats consecrated for different days may be sacrificed, this one in place of that one? For example: if a goat was initially consecrated to be sacrificed as part of the Yom Kippur additional offerings, may it be sacrificed as part of the Festival additional offerings instead? R' Shimon said to them: They may be sacrificed. They said to him: Since, according to you, their atonement is not the same, how could they possibly be sacrificed, this one in place of that one? R' Shimon said to them: They can be interchanged, since ultimately all of them come to atone for the defiling of the Temple or its sacrificial foods.