Mishnayos Shevuos Perek 1 Mishnah 5

Rabbi Shimon ben Yehuda says in the name of Rabbi Shimon a tradition of his opinion that differs from the way the mishna expresses it above: The goats of the New Moons atone for a ritually pure person who unwittingly partook of ritually impure sacrificial food. The goats of the Festivals exceed them, as they atone both for a pure person who partook of impure sacrificial food and also for cases of defiling the Temple or its sacrificial foods in which one did not have awareness, neither at the beginning nor at the end. The goats of Yom Kippur further exceed them, as they atone both for a ritually pure person who partook of ritually impure sacrificial food and for cases of defiling the Temple or its sacrificial foods in which one did not have awareness, neither at the beginning nor at the end; and they also atone for cases in which one did not have awareness at the beginning but did have awareness at the end. 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? Rabbi Shimon said to them: Yes, they can be interchanged. They said to him: If what you say is so, granted that the goats of Yom Kippur may be sacrificed on the New Moons, but how could the goats of the New Moons be sacrificed on Yom Kippur when they will need to effect atonement for that which they were not consecrated for? Rabbi Shimon said to them: They can all be interchanged, since ultimately all of them come to atone for the defiling of the Temple or its sacrificial foods, even if each one atones for a different case.

רַבִּי שִׁמְעוֹן בֶּן יְהוּדָה אוֹמֵר מִשְּׁמוֹ, שְׂעִירֵי רָאשֵׁי חֳדָשִׁים מְכַפְּרִין עַל טָהוֹר שֶׁאָכַל אֶת הַטָּמֵא. מוֹסִיף עֲלֵיהֶם שֶׁל רְגָלִים, שֶׁמְּכַפְּרִין עַל טָהוֹר שֶׁאָכַל אֶת הַטָּמֵא וְעַל שֶׁאֵין בָּהּ יְדִיעָה לֹא בַתְּחִלָּה וְלֹא בַסּוֹף. מוֹסִיף עֲלֵיהֶם שֶׁל יוֹם הַכִּפּוּרִים, שֶׁהֵן מְכַפְּרִין עַל הַטָּהוֹר שֶׁאָכַל אֶת הַטָּמֵא, וְעַל שֶׁאֵין בָּהּ יְדִיעָה לֹא בַתְּחִלָּה וְלֹא בַסּוֹף, וְעַל שֶׁאֵין בָּהּ יְדִיעָה בַתְּחִלָּה אֲבָל יֶשׁ בָּהּ יְדִיעָה בַסּוֹף. אָמְרוּ לוֹ, מַהוּ שֶׁיִּקְרְבוּ זֶה בָזֶה. אָמַר לָהֶם, הֵן. אָמְרוּ לוֹ, אִם כֵּן, יִהְיוּ שֶׁל יוֹם הַכִּפּוּרִים קְרֵבִין בְּרָאשֵׁי חֳדָשִׁים, אֲבָל הֵיאַךְ שֶׁל רָאשֵׁי חֳדָשִׁים קְרֵבִין בְּיוֹם הַכִּפּוּרִים לְכַפֵּר כַּפָּרָה שֶׁאֵינָהּ שֶׁלָּהּ. אָמַר לָהֶן, כֻּלָּן בָּאִין לְכַפֵּר עַל טֻמְאַת מִקְדָּשׁ וְקָדָשָׁיו: