The law was given through angels and entrusted to a mediator.(Gal 3:19)
For since the message spoken through angels was binding, and every violation and disobedience received its just punishment, how shall we escape if we ignore so great a salvation?(Heb 2:2-3)
Where does this idea come from? It can not be found in Genesis, in fact, it can not be found anywhere in the Scriptures, yet Luke, Paul, and the author of Hebrews attest to is truthfulness. The author of Hebrews uses it for theological support to say the law of Moses is inferior to the New Covenant of Christ, since the former was given by mere angels, and the latter by Christ Himself.
Paul writes Timothy about deceivers in the church and mentions two individuals,
Who are these men, Jannes and Jambres? They too are not mentioned anywhere in the Scriptures, but both Paul and Timothy seem to know who they are. This is a tradition passed on, outside of the scriptures, that Paul takes to be authoritative.
Jude makes reference to two traditions outside of scripture,
The story of the dispute over the body of Moses is found nowhere in the scriptures, but comes from the book, “The Assumption of Moses”. The prophecy of Enoch comes from, “The Book of Enoch” which was written about two centuries before Christ. Stranger still, is that Enoch’s life took place before Noah! So Jude is referencing two passages that are extra-biblical and considers them to be authoritative.
In Hebrews, we also find a reference to an extra-biblical source passed down by tradition,
There are many instances of people in the Old Testament being mocked, and stoned, and slain by the sword, but there is not one story of anyone being sawn in two. This comes from the “Ascension of Isaiah 5:1-14 which describes the way in which Isaiah dies.
Now no Christian group has ever considered the Assumption of Moses, the Book of Enoch, or the Ascension of Isaiah inspired scripture, so what is going on here? A real tradition is being preserved in an otherwise uninspired book. The biblical writers are getting their information about God exactly the way Paul said they should, by tradition, both oral and written.