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 15

15:18 The woman also with whom man shall lie with seed of copulation, they shall both bathe themselves in water, and be unclean until the even.