There is a myth going around that needs to be dealt with. That myth is that the Bible is a “self-referencing book”.
This myth is based on a category error.
The error is that the Bible is “just” a book when, literarily, the Bible is best considered as an anthology, a collection of works surrounding the same subject. The Christian Scriptures, which consists of two parts, the Old and New Testaments, are anthologies in their own rights: the former dealing with God’s interactions with the nation of Israel, the latter working as an exposition on the former.
Now that we’ve established the proper categories, when the texts contain a reference to another work in that collection, there is no “self-reference”, rather what we have are texts that share a common theme over a period of time gathered together in one location showing not only a progression in thought on the subject, but a remarkable consistency over more than a thousand years of writing, so that the reader will not have to run around looking for the texts that are being referenced.
It would be best described as a convenience package.