Yoma, 60a: One precludes from Chukah ¹ Avodah that the Kohen Gadol performs in the wrong order wearing the Bigdei Lavan in the Heichal; ² the other, to preclude Avodah that he performs wearing wearin the Bigdei Zahav.

Seforno: It teaches us that Yom Kipur atones even when there is no Mikdash and no Avodah. ¹

Refer to 16:34:151:1-3.

Oznayim la'Torah: Because Hashem knew that, if Yisrael are not cleansed from their sins once a year, their sins would accumulate and grow from Chata'os to Pesha'im, since that is the way of the Yeitzer-ha'Ra - Today he says 'Do this!'; tomorrow, 'Do that!', until eventually, he convinces a person to serve Avodah Zarah! Consequently, Yom Kipur weakens the poweer of the Yeitzer-ha'Ra ¹

Rashi #1: To teach us that Aharon did everything mentioned above when Yom Kipur arrived.

Rashi #2: To teach us that Aharon wore the Bigdei Kehunah, not because of the Kavod that they afforded him, but in order to carry out the command of Hashem.

Ramban: To teach us that, for the reat of his life, Aharon was careful never to enter the Kodesh Kodashim except on Yom Kipur with the prescribed Korbanos.

Seforno (31,34): Verse 31 teaches that even when there is no Mikdash, there is Iruy and we cease from Melachah. Our verse teaches that Yom Kipur atones even when there is no Mikdash.

Toras Moshe: Even if Yisrael did not sin at all, Yom Kipur 'atones' for them to raise them to a higher level.