This thought stemming from my reading of the long and classy introduction to the book of Jeremiah by Jack Lundbom in his vast commentary that makes up 3 vols. of the Anchor Bible series… see his Jeremiah 1-20, 105-106.
Critical scholarship for a long time believed and often still believes that the law book that was found in the temple in the 18th year of the reign of king Josiah (i.e. about 622 BC) according to 2 Kings 22:3-10 consisted of a large middle portion of what we know now as the book of Deuteronomy. This is seen to be the catalyst for Josiah’s ensuing reformation of religion in the Judah of his day, which particularly sought to purify worship of Yahweh by eliminating religious ritual in outlying sanctuaries and restricting it to the temple in Jerusalem. The narrative in 2 Kings 23 in fact focuses on the destruction of pagan altars outside of Jerusalem, but texts like 1 Kings 3:2 imply that a more thorough program of centralization of worship was undertaken. This interpretation of the cause-and-effect relationship, that the law book inspired Josiah’s reformation, is clearly supported by the order of events in the Kings narrative.
Lundbom, however, says, “More recently, however, the Chronicler’s account has been given preference,” referring to 2 Chronicles 34, where the reason the law book is found in the temple is that Josiah has already, from 628 BC, undertaken religious reforms of the kind that led to the temple’s renovation. This sequence has a certain credible logic to it. Without such reform, no renovation might be expected. Chronicles has usually been regarded as an inferior historical source to Kings, partly by virtue of being clearly composed later and being somewhat derivative in relation to Kings. But every history has agendas or axes to grind, and the editor of Kings may in fact want to show that the Law of Moses in textual acts as an effective catalyst for religious renewal. As an instance of Chronicles’ stricter historical accuracy, I think of its faithful relaying of the names of Saul’s sons despite their being compounded on the name of the rival god Baal (1 Chron. 8:33-34). In any case, it is interesting to consider the alternative possibility that the discovery of the law book might have been the culmination for Josiah’s reforms rather than their initial catalyst.
As a footnote to this, Lundbom adds another unique suggestion – that the law book discovered in the temple was not the body of Deuteronomy at all, but the poem, some (esp. from the Albright school) would say ancient, known as the Song of Moses and found in Deuteronomy 32. Often when I have sought to trace archaic or potentially archaic language through the Old Testament, it has appeared in this unique poem along with other well-known texts such as the Song of the Sea in Exodus 15 and the Song of Deborah in Judges 5. I am not yet in a position to evaluate Lundbom’s suggestion, but it shows an ability to stand outside of the mainstream consensus and find new answers to old questions, which is always good for keeping our thinking flexible!