Leviticus can also be called “The Book of the Law of the Priests” as it contains very little historical matter, concerning itself with priestly legislation and the practice of the Law among the people. Much importance is placed upon Israel’s separation from all heathen influences so that the nation may retain its religious purity.

Leviticus 16

16:2 And the LORD said unto Moses, Speak unto Aaron thy brother, that he come not at all times into the holy place within the veil before the mercy seat, which is upon the ark; that he die not: for I will appear in the cloud upon the mercy seat.