2 and Yahweh said to Moses, "Tell Aaron your brother not to come at just any time into the Most Holy Place within the veil, before the mercy seat which is on the ark; lest he die; for I will appear in the cloud on the mercy seat.
14 He shall take some of the blood of the bull, and sprinkle it with his finger on the mercy seat on the east; and before the mercy seat he shall sprinkle some of the blood with his finger seven times.
15 "Then he shall kill the goat of the sin offering that is for the people, and bring his blood within the veil, and do with his blood as he did with the blood of the bull, and sprinkle it on the mercy seat and before the mercy seat.
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.