If neither technical terms nor attributions are available for separating a text from its context, a change in formulation and style may help to determine its beginning and end. For example, a parable or story will be recognizable by its narrative style, if it is preceded by a legal statement or discussion. Problems arise in the case of longer narratives, which are especially common in the Babylonian Talmud, may be composed of several originally independent units. The building blocks and seams of such narratives may be detected by paying attention to the changing thematic focus, changing personages and/or settings, and parallel formulations (an indication of editorial intervention). Sometimes, editorial continuations of stories are recognizable. Editors may have tried to expand the scope of applicability of a case story, to make it applicable to a greater variety of circumstances besides those explicitly addressed in the tradition. If such an expansion fits the concerns of the discussion surrounding the text, the “final” editors may be considered responsible for its formulation. Otherwise, the expansion may have happened at the pre-redactional stage already.
Catherine Hezser, “Form-Criticism of Rabbinic Literature”, in The New Testament and Rabbinic Literature, eds. Reimund Bieringer, Florentino García Martinez, Didier Pollefeyt and Peter J. Tomson (Leiden & Boston: Brill, 2010), 100.