The fifth book in the Pentateuch, which includes the Decalogue (= Exod. 20: 2–17), is fundamental to God’s covenant with Israel; this relationship is particularly expressed in the Sabbath regulations (5: 12–15). In a sense the Decalogue also expresses the divine will for mankind as a whole, and has accordingly been used in Christian Churches as a valid exposition of human duties towards both God and neighbour. Because human nature is contaminated with wickedness, law acts as a restraint on hardness of heart.
There is a dramatic account (2 Kgs. 22: 8 ff.) of the discovery of a law book during restoration work in the Temple in 621 BCE. It prompted Josiah the king to expedite his religious and social reforms, which corresponded to the outlook of Deuteronomy. It has therefore been supposed that the book allegedly discovered was an early form of the book Deuteronomy, or some of it.
The book is part law and part prophecy. As the last book in the Torah, it completes the account of Moses which began with his birth (Exod. 2: 12). It also ushers in the nation’s history from Judges to the end of 2 Kings, and the laws in Deuteronomy furnish the yardstick by which the actions of kings and peoples are assessed. So the book extols belief in Yahweh as the only God. Its existence encouraged its study and promotion by appropriately educated scribes. The aim of the book is to bring the whole of Israelite life under a sense of duty to God and thanksgiving for his great acts in the past history of the nation (Deut. 16: 3). It was therefore not inappropriately ascribed to Moses, lawgiver (Exod. 24: 12) and prophet (Deut. 34: 10), but this traditional view should not be understood literally. Not only does the book describe Moses’ death (34: 1–12), but the contents reflect an editorial process of reinterpretation so that old traditions were made relevant for changed historical situations. It was an attempt to maintain the vitality of Hebrew worship (Deut. 6: 13–15) and the prophets’ demands for social justice (Deut. 15: 1–18). The compilation has been dated in the 7th cent. BCE, but the account in the Deuteronomist book 2 Kgs. 25 of the release of Jehoiachin from prison suggests a date for its final publication to be soon after 561 BCE. Obviously its authors were literate; but it does not follow that the general population was too: it remained a predominantly oral society.