The Book of Deuteronomy is the fifth book of the Bible and the last of the Pentateuch or Torah, the five books written by Moses. Deuteronomy contains three sermons given by Moses to the Israelites who are to enter the promised land. The word Deuteronomy means 'second law giving' as the book reiterates the laws God has given to His people for the generation of Israelites who were not present when the laws were first given.
"Hear, O Israel: The Lord our God is one Lord: and thou shalt love the Lord thy God with all thine heart, and with all thy soul, and with all thy might."
Jesus Christ Himself said that this was the greatest of all commandments in the Book of Mark 12: 28-34