What does scripture say about adding or DELETING to it?
Here is why the bible is a Catholic book.
https://www.catholic.com/qa/didnt-the-catholic-church-add-to-the-bible
First off, the Catholics added to it, they are the ones who added non inspired writings.
Besides there was no Catholic Church until years after the cannon was closed.
I am going to stop this discussion now, because any faith that would think they need a High priest over Christ is lost.