Deuteronomy — the fifth and final book of the Pentateuch — is Moses’ farewell. The book opens on the plains of Moab opposite Jericho, the same staging-ground where Numbers closed; Moses, knowing he will not cross the Jordan, gathers the new generation for sustained covenantal exhortation. The book’s Hebrew title is Devarim (“words” — from “These are the words which Moses spake unto all Israel,” 1:1). The Greek Septuagint titles it Deuteronomion (“second law”), from Deut 17:18’s mishneh ha-Torah — the king’s required “copy of this law.” The English title preserves the LXX form.
The book unfolds in three sustained speeches. Moses’ first speech (Deut 1-4) is a historical retrospective: Moses retells the wilderness journey to the new generation — Horeb, the spies, the forty-year sentence, the wilderness through Edom and Moab and Ammon, the defeat of Sihon and Og, the trans-Jordan allocation — and turns the retrospective into covenantal call. Moses’ second speech (Deut 5-26) is the book’s heart: the Decalogue recapitulated (chapter 5), the Shema as the central confession (chapter 6 — Deuteronomy 6:4–5↗, “Hear, O Israel: the LORD our God is one LORD”), and the extended exposition of the law that organizes Israel’s life in the land. Moses’ third speech and the closing (Deut 27-34) contains the covenant ceremony at Gerizim and Ebal (chapters 27-28’s blessings and curses), the third speech proper, the Song of Moses (chapter 32), Moses’ blessing of the tribes (chapter 33), and Moses’ death (chapter 34).
The book is structurally distinctive within the Pentateuch. Where Numbers narrated events in third person, Deuteronomy is sustained first-person speech: Deuteronomy 5:1↗‘s “Hear, O Israel” begins the second speech; the hortatory register dominates throughout. The Hebrew word “heart” saturates these chapters: love the LORD with all your heart (6:5); these words shall be in thine heart (6:6); circumcise the foreskin of your heart (10:16). The book is the OT’s most-developed single piece of heart-covenant theology.
The book’s place in the canon is doubly significant. It closes the Torah (the fifth Pentateuchal book) and opens the broader narrative thread that the Deuteronomistic History (Joshua-Judges-Samuel-Kings) presupposes — the framework by which Israel’s later success or failure in the land will be measured against the book’s covenantal terms. The book Jewish liturgical tradition returns to daily (the Shema at Deuteronomy 6:4–5↗ is the central confession of Jewish faith, recited morning and evening); the book Jesus cites most heavily in His temptation in the wilderness (Matthew 4:1–11↗ and Luke 4:1–13↗ quote Deut 6:13, 6:16, and 8:3 against the three temptations); the book Paul reaches into for foundational Christian-monotheistic vocabulary (Romans 10:8↗‘s “the word is nigh thee, even in thy mouth, and in thy heart” cites Deut 30:14). The book ends with Moses on Mount Nebo, the LORD showing him the land he will not enter, and the Pentateuch closes with the prophet’s death and the people on the threshold of the conquest.