I came across a few great quotes in Michael Fishbane’s Biblical Interpretation in Ancient Israel (hereafter BIAI) on aggadic (i.e., non-halakhic) exegesis. Fishbane notes how this type of exegesis is utilized by the OT writers as they pick up and re-employ earlier traditions.
After noting that aggadic exegesis not only has different concerns than does halakhic exegesis, there are also a different cause for – or purpose to – the exegesis. In the case of halakhic exegesis, the concern is to make “pre-existent laws applicable or viable in new contexts” (BIAI, pg. 282). With aggadic exegesis, however, things are different. “[I]t may be said that the existence or perception of some lack in the traditum [original source text or tradition] is a significant condition for the rise of legal exegesis. . . . In contrast to legal exegesis, fullnessis a significant condition for its [aggadic exegesis] emergence” (BIAI, pg. 282).
Here’s a few paragraphs of note:
Aggadic exegesis is thus not content to supplement gaps in the traditum, but characteristically draws forth latent and unsuspected meanings from it. In this way, aggadic exegesis utilizes the potential fullness of received formulations and makes this potential actual. For if inner-biblical legal exegesis particularly serves to fill a felt lack in the traditum, and to clarify for all practical or theoretical purposes the plain sense of a Scriptural dictum, inner-biblical aggadic exegesis, by contrast, gives particular emphasis to its sensus plenior, its fullness of potential meanings and applications. Legal exegesis and aggadic exegesis thus illumine different facets of a text’s inherent possibilities: the one, legal exegesis, shows how a particular law can be clarified and reinterpreted qua law; while the other, aggadic exegesis, characteristically shows how a particular law (or topos, or theologoumenon) can transcend its original focus, and become the basis of a new configuration of meaning.
BIAI, pg. 283.
Regarding the re-use of traditions:
[I]t has been repeatedly contended by A. Robert and his followers that a style defined as procede anthologique ‘re-employs, literally or equivalently, words or formulas of earlier scriptures’, that is, that the earlier biblical texts are exegetically reused, or ‘reactualized’, in new contexts. In some cases ‘the author preserves the literal meaning of his predecessor [texts] but applies it to another object’; in other instances, older terms are extended, transposed, or otherwise given new significance
BIAI, pgs. 286-87.
Finally, on typology:
Typological exegesis thus celebrates new historical events in so far as they can be correlated with older ones. By this means it also reveals unexpected unity in historical experience and providential continuity in its new patterns and shapes. Accordingly, the perception of typologies is not solely an exegetical activity, it is, at the same time, a religious activity of the first magnitude. For if legal and other aggadic exegeses emphasize the verbal aspects of ongoing divine revelation, typological exegesis reveals its historical concreteness. Typological exegesis is thus not a disclosure of the sensus plenior of the text, in the manner of other forms of inner-biblical exegesis. It is rather a disclosure of the plenitude and mysterious workings of divine activity in history.
BIAI, pg. 352.
BIAI is really the gift that keeps on giving as quote upon quote, with no end in sight, could be lined up on this post! Fishbane has a given a very detailed examination of the earliest hermeneutic used by the biblical writers. Though the book does cost a pretty penny, it is still an great resource!