The main teaching of this book is the holiness of God and the ways in which the people of Israel were to worship Him and live in order to maintain their relationship with Him. This relationship was established by the Sinai covenant.

The book deals with the laws and a set of principles which were established so that the holiness of God and of His people could be maintained.

The priests were the ones responsible for overseeing maintenance of this relationship. They had to mediate between God and His people through building  altars and offering sacrifices.

The house of Levite was the one chosen for priestly duties among the twelve tribes of Israel (Exodus 32:29).