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 18

18:9 The nakedness of thy sister, the daughter of thy father, or daughter of thy mother, whether she be born at home, or born abroad, even their nakedness thou shalt not uncover.