וְכִפֶּ֤ר אַהֲרֹן֙ עַל־קַרְנֹתָ֔יו אַחַ֖ת בַּשָּׁנָ֑ה מִדַּ֞ם חַטַּ֣את הַכִּפֻּרִ֗ים אַחַ֤ת בַּשָּׁנָה֙ יְכַפֵּ֤ר עָלָיו֙ לְדֹרֹ֣תֵיכֶ֔ם קֹֽדֶשׁ־קָֽדָשִׁ֥ים ה֖וּא לַיהוָֽה׃ (פ)
И Аарон будет очищать его на рогах один раз в год; кровью жертвы за грех за искупление один раз в год искупит ее на протяжении поколений ваших; это самое святое для Господа.'
Ramban
THAT HE COME NOT AT ALL TIMES INTO THE HOLY PLACE WITHIN THE VEIL. The meaning of the expression at all times is that since He had already mentioned the Day of Atonement, saying, And Aaron shall make atonement upon the horns of it [i.e., the golden altar which stood within the Sanctuary] once in the year,20Exodus 30:10. therefore He stated here that Aaron is not to come at any time into the holy place [within the Veil], except with this21Verse 3 here. [procedure], that is to say, on the day that he brings these offerings to effect atonement. Later on in this section He explains with what Aaron shall enter, just as He said, and he shall bring it within the Veil,22Verse 12. and then He specifies the day, that it be in the seventh month, on the tenth day of the month,23Verse 29. and then He states again that it be [only] once in the year.24Verse 34.
Tur HaArokh
He had already been told to enter the Holy of Holies only once a year on the Day of Atonement, as we know from Exodus 30,10 וכפר אהרן על קרנותיו אחת בשנה, “he is to secure atonement on its corners once a year by the sin offering of atonement, etc. This is what has been referred to in our verse here.
English Explanation of Mishnah Yoma
“And he shall go out to the altar that is before the Lord” (Leviticus 16:18): that is the golden altar. The mishnah identifies the altar mentioned in v. 18 with the golden altar inside the Hekhal, upon which the incense is offered. This is explicit in Exodus 30:10 which in reference to this golden incense altar states, “Once a year Aaron shall perform purification upon its horns with blood of the sin offering of purification; purification shall be performed upon it once a year throughout the ages. It is most holy to the Lord.”