出エジプト記 29:36

על הכפרים means for the purpose of expiation — to expiate for the altar for all that is “strange” (not holy) and objectionable that may happened to it. Now since it is said. (v. 35) “Seven days shalt thou consecrate them” after having stated that if a single thing is omitted the ceremony is invalid, I can infer nothing more than that this alludes to a thing that is offered on account of them personally as, for example, the rams and the bread, but as regards anything that is offered on account of the altar as, for example, the bullock, which is intended to serve as expiation for the altar, we cannot infer from that verse that if this is omitted the ceremony of initiation is invalid; consequently this verse is necessary to inform us of this. An explanation in Torath Cohanim (the Sifra) states: atonement for the altar was necessary because perhaps a man had donated for work in connection with the construction of the Tabernacle or the altar something which he had stolen (Sifra, Tzav, Mechilta d'Miluim 1 15). וחטאת — The Targum translates this by ותדכי AND THOU SHALT PURIFY [THE ALTAR]; the expression for placing upon the altar the blood that is placed there with the finger is called חַטַּא (hence it is followed by the preposition על “upon”). ומשחת אתו AND THOU SHALT ANOINT IT with the oil of anointing: every anointing was done in the form of a Greek Chi (X).

וּפַ֨ר חַטָּ֜את תַּעֲשֶׂ֤ה לַיּוֹם֙ עַל־הַכִּפֻּרִ֔ים וְחִטֵּאתָ֙ עַל־הַמִּזְבֵּ֔חַ בְּכַפֶּרְךָ֖ עָלָ֑יו וּמָֽשַׁחְתָּ֥ אֹת֖וֹ לְקַדְּשֽׁוֹ׃

And thou shalt offer every day a bullock for a sin offering for atonement: and thou shalt cleanse the altar, when thou hast made atonement for it, and thou shalt anoint it, to sanctify it.