We are free, then, to consider the date of Deuteronomy by an examination of the internal evidence. The latest possible date for the book, as a whole, is determined by the story of its discovery in 621 B.C. (2 Kings xxii., xxiii.). There can be no doubt that the book then discovered by the priest Hilkiah, and read by the chancellor before the king, was Deuteronomy. It is called the book of the covenant (2 Kings xxiii. 2), but it clearly cannot have been the Pentateuch. For one thing, that was much too long; the book discovered was short enough to have been read twice in one day (2 Kings xxii. 8, 10). And again, the swift and terrible impression made by it could not have been made by a book so heterogeneous in its contents and containing romantic narratives such as the patriarchal stories. Nor again can the discovered book have been Exodus xxi.-xxiii., though that is also called the book of the covenant (Exod. xxiv. 7); for some of the most important points in the succeeding reformation are not touched in that book at all. It is clear from the narrative in 2 Kings xxii. ff. that the book must have been a law book; no other meets the facts of the case but Deuteronomy, and this meets them completely. Point for point, the details of the reformation are paralleled by injunctions in Deuteronomy--notably the abolition of idolatry, the concentration of the worship at a single sanctuary (xii.), the abolition of witchcraft and star-worship, and the celebration of the passover. Some of these enactments are found in other parts of the Pentateuch, but Deuteronomy is the only code in which they are all combined. 621 B.C. then is the latest possible date for the composition of Deuteronomy.