פירוש על ויקרא 16:34

'ויעש כאשר צוה וגו AND HE DID AS [THE LORD] COMMANDED [MOSES] etc. — When the next Day of Atonement arrived he (Aaron) did everything as is here set forth in order. And Scripture only states this in order to declare the praise of Aaron — that he did not attire himself with them (the official garments) for his own aggrandisement, but as one who was executing the ordinance of his King (Sifra, Acharei Mot, Chapter 8 10).

AND HE DID AS THE ETERNAL COMMANDED MOSES. This means that Aaron fulfilled all that he was commanded, and he was careful all his life not to enter the Holy of Holies except on the Day of Atonement in order to bring his offerings, according to all that G-d commanded Moses.

והיתה זאת לכם לחקת עולם לכפר, that the very day itself has the power to confer atonement even when there is neither a Temple nor a Temple service. In the words of our sages (Yuma 86) “repentance suspends the imposition of retribution and the arrival of the date of the Day of Atonement completes the atonement.”