Leviticus 16:2-3

New King James Version

² and the Lord said to Moses: “Tell Aaron your brother ^(A)not to come at just any time into the Holy Place inside the veil, before the mercy seat which is on the ark, lest he die; for ^(B)I will appear in the cloud above the mercy seat.

^3 [a]“Thus Aaron shall ^(C)come into the Holy Place: ^(D)with the blood of a young bull as a sin offering, and of a ram as a burnt offering.