The theme of Leviticus is “Holiness. This book by Moses is devoted to worship by the redeemed people, the Israelites. This is shown by the frequent use of words concerning “holiness” and “sacrifice.” The topic of sacrifice pervades the book. The words "holiness" and "holy," appear more than 150 times. Also, God’s commandment is often repeated, "You shall be holy, for I am holy." 

Deuteronomy means “The Second Law” with the theme “The Law Restated.” The book was written by Moses at about the same time as Leviticus. Deuteronomy begins with an overview of the history of Israel, then reviews the basic laws of the preceding books [Genesis, Exodus, Leviticus, and Numbers] and concludes with a series of prophecies of the Israelite final return to Palestine.