Anyways, the Documentary Hypothesis hypothesises that the Old Testament (especially the Torah) is basically a collection of potentially related but essentially independent stories which have been brought together by editors (redactors). The different sources who have been brought together have been identified as 'J' (Jahwist) 'E' (Elohist) 'D' (Deuteronomist) and 'P' (Priestly). As a side note, this led to the Jed P. joke in the OT part of my Moore Revue video which I assumed went over most people's heads.
This is what Paul Wiliamson has to say on the theory in our Old Testament 2 lecture notes regarding the promise of land to Israel being both unconditional and provisional in nature.
Those looking at the text through a diachronic lens see the explanation of such a paradox in the editorial layers allegedly underlying the final form of the text.16 All such theories, however, ultimately come up against the insuperable problem of why redactors would wish to combine two antithetic traditions, or qualify the tradition of an unconditional promise on such a selective basis themselves.In other words, as I've said many times, this theory works on the assumption that the editor was an idiot.
The whole hypothesis arises from the fact that you can see the 'seams' of the editing process. And yet others argue we should worry where we can't see the seams, because it has been edited too well. But you can't have it both ways. If both evidence of multple sources and lack of evidence of multiple sources indicate multiple authorship, what evidence would you need to prove the writing is something close to a single author?