The scholarly methodology that led to the positing of the existence of a Deuteronomistic school is redaction criticism. Redaction criticism grew out of a weariness with source criticism and other forms of biblical criticism that fragmented the text into older sources, genres, or tradition units in order to arrive at a history of Israelite religion, with little attention to how the text reached its final form. Redaction criticism rejects the idea that the person or persons who compiled the text from early sources and tradition units did a mechanical scissors-and-paste job. Redaction criticism focuses on identifying the purpose and plan behind the final form of the assembled sources in order to uncover the intention of the person or persons who produced the biblical text in roughly the shape we have it.
Redaction criticism proceeds in the following manner: First, one can usually identify linking passages—passages that join narratives or other units together in an attempt to make the text read smoothly and ease the transition from one source to another. These are assigned to R, the redactor. Also assigned to R are interpretive additions, passages that stand back and comment on or interpret the text—in short, any place where the narrator turns to address the reader directly in order to explain something.
For example, statements like “the Canaanites, and Perizzites were then dwelling in the land” (Gen 13:7) or “they tore down the temple of Baal and turned it into latrines, as is still the case” (2 Kgs 10:27) break with the train of the narration in order to comment from the perspective of a later time (the time of the author of the statement). Similarly, etiological comments such as “that is why the children of Israel do X to this day” provide a chronologically later interpretation of the main text. Sometimes a story or book contains a preface that indicates, justifies, or otherwise comments on what is about to be related (Jud 2–3:4), while some passages summarize and offer an interpretation of or justification for what has just been related (2 Kgs 17).
By joining together the passages assigned to R, one often sees stylistic similarities and a consistent point of view rarely found in the actual source material that these passages frame. In this way, a clearer understanding of the role of the redactor in the final production of the text and of the redactor’s own historical situation, his purposes, and concerns emerges.
Elizabeth Hayes, Christine. Introduction to the Bible (The Open Yale Courses Series) (pp. 230-231). Yale University Press. Kindle Edition.