This was the most important day of the year. The whole nation having had their sins previously forgiven by the atonement made in the Holy, now assemble about their Sanctuary, while the High Priest, attired in his holy garments for glory and beauty, verse 4, Exodus 28, having the golden bells on the hem of his robe that his sound may be heard when he goeth in before the Lord, the breast-plate of judgment on his heart, with their names therein that he may bear their judgment, also in it the Urim and Thummim (light and perfection), and the plate of pure gold, the holy crown , (Leviticus 8:9, Exodus 28:36), with " HOLINESS TO THE LORD " engraved upon it, placed upon the fore-front of his mitre that he may bear the iniquities of the holy things, enters the Holy of Holies to make an atonement to cleanse them , that they may be clean from all their sins before the Lord, verse 30. The victims for the atonement of this day were, for the priest himself, a young bullock for a sin-offering, verse 3, and for the people, two goats; one for a sin-offering and the other for the scape-goat, and a ram for a burnt-offering, verses 5-8.
He killed or caused to be killed the bullock for a sin-offering for himself, verse 11. "Then he shall take a censer full of burning coals office from off the altar before the Lord, and his hands full of sweet incense beaten small, and bringing it within the veil; And he shall put the incense upon the before the Lord, that the cloud of the incense may cover the mercy-seat that is upon the testimony that he die not. And he shall take of the blood of the bullock, and sprinkle it with finger upon the mercy-seat eastward; and before the mercy-seat shall he sprinkle of the blood with finger seven times," verses 12-14. So much in preparation to make an atonement for the people; a description of which follows: "Then shall he kill the goat of the sin-offering which is for the people and leaving [bring] his blood within the veil, and do with that blood as he did with the blood of the bullock, and sprinkle it upon the mercy-seat.
And he shall make an atonement for (cleanse, see marginal references,) the holy place (within the veil, verse 2), because of the uncleanness of the children of Israel , because of their transgressions in all their sins: and so shall he do for (i.e. atone for or cleanse), the tabernacle of the congregation (the Holy) that remaineth among them in the midst of their uncleanness," verses 15, 16; "And he shall go out (of the Holy of Holies) unto the altar that is before the Lord (in the Holy) and make an atonement for it; and shall take of the blood (for himself), and of the blood of the goat (for the people), and put it upon the horns of the altar round about. And he shall sprinkle of the blood upon it with finger seven times, and cleanse it , and hallow it from the uncleanness of the children of Israel," verses 18, 19. The altar was the golden altar of incense in the Holy upon which the blood of individual atonements was sprinkled during the daily ministration.
Thus it received the uncleanness from which it is now cleansed.