Leviticus 16:32-34

World English Bible

³² The priest, who is anointed and who is consecrated to be priest in his father’s place, shall make the atonement, and shall put on the linen garments, even the holy garments. ³³ Then he shall make atonement for the Holy Sanctuary; and he shall make atonement for the Tent of Meeting and for the altar; and he shall make atonement for the priests and for all the people of the assembly.

³⁴ “This shall be an everlasting statute for you, to make atonement for the children of Israel once in the year because of all their sins.”

It was done as Yahweh commanded Moses.