"The Book of Deuteronomy ... is the fifth book of the Hebrew Bible, and of the Jewish Torah," according to Wikipedia. 'The Hebrew title is taken from the opening phrase Eleh ha-devarim, "These are the words. ...'
"The English title is from a Greek mistranslation of the Hebrew phrase mishneh ha-torah ha-zoth, 'a copy of this law', in Deuteronomy 17:18, as to deuteronomion touto — 'this second law.'
"In German, this book is also called Mose, the book of Moses, taking this title from the opening line, "These are the words of Moses. ....'
"The book consists of three sermons or speeches delivered to the Israelites by Moses on the plains of Moab, shortly before they enter the Promised Land.
"The first sermon recapitulates the 40 years of wilderness wanderings which have led to this moment, and ends with an exhortation to observe the law (or teachings), later referred to as the Law of Moses; the second reminds the Israelites of the need for exclusive allegiance to one God and observance of the laws (or teachings) he has given them, on which their possession of the land depends; and the third offers the comfort that even should Israel prove unfaithful and so lose the land, with repentance all can be restored.
"Traditionally seen as the words of Moses delivered before the conquest of Canaan, modern scholarship sees its origins in traditions from Israel (the northern kingdom) brought south to the Kingdom of Judah in the wake of the Assyrian destruction of Samaria (8th century BC) and then adapted to a program of nationalist reform in the time of King Josiah (late 7th century), with the final form of the modern book emerging in the milieu of the return from the Babylonian exile during the late 6th century.
"One of its most significant verses is Deuteronomy 6:4, the Shema, which has become the definitive statement of Jewish identity: 'Hear, O Israel: the LORD our God, the LORD is one.'
"Verses 6:4–5 were also quoted by Jesus in Mark 12:28–34 as part of the Great Commandment."