1. The New Testament Canon was not decided by any church council.
The church councils did not decide what was canonical... Click on the source link below for more.
2. Early Christians believed that canonical books were self-authenticating.
Another authenticating factor was the internal qualities of each book... Click on the source link below for more.
3. The New Testament books are the earliest and best Christian writings we have.
The New Testament books are the earliest writings we possess regarding Jesus... Click on the source link below for more.
4. The New Testament book come to us directly from apostolic testimony.
Unlike any book from that period or the following century, the New Testament books were directly connected to the apostles and their testimony of the resurrected Christ... Click on the source link below for more.
5. New Testament writers quote other New Testament writers as Scripture.
The belief in new revelation or a testament of books was not a late development... Click on the source link below for more.
6. Early Christians used noncanonical writings without analogous authority.
Christians often cited noncanonical literature with positive affirmation for edification... Click on the source link below for more.
7. The New Testament documents are the best ancient manuscript tradition we have and were reliably chosen.
We have over 5,800 Greek manuscripts of the New Testament... Click on the source link below for more.
The evidence for our New Testament writings is ever so much greater than the evidence for many writings of classical authors, the authenticity of which no-one dreams of questioning. And if the New Testament were a collection of secular writings, their authenticity would generally be regarded as beyond all doubt. It is a curious fact that historians have often been much readier to trust the New Testament than have many theologians (F.F. Bruce, The New Testament Documents: Are They Reliable?).
These realities should comfort us, not only in knowing why we have the books in the New Testament that we do, but that our translations and copies are reliable and trustworthy due to the overwhelming internal and external evidence.