Have you ever wondered how the Bible was put together? I mean, how do we know that the Book of Ephesians is part of the inspired Word of God and that the Gospel of Thomas is not part of the inspired Word of God?
Here are the six criteria the early Church used to determine which books were truly from God and belong in your Table of Contents:
Criteria for Canonicity
1) Written by recognized prophet or apostle.
These are books or letters written by Paul, Peter, John, Jeremiah, Moses, etc. This covers most of the OT and NT books.
2) Written by someone associated with a recognized prophet or apostle.
This would include The Gospel according to Luke. Luke was not an apostle, but Luke was a companion of Paul, so the Gospel of Luke is backed by Paul’s apostleship.
Since God speaks truth, falsehood cannot be from God. So any book or letter found with error or contradictions is a book that is obviously not from God.
4) Faithfulness to previously accepted canonical writings.
This means if a new letter showed up that contradicted what scripture had previously taught, this letter would be judged as false. So when the so called Gospel of Thomas appeared several hundred years after the writings of the apostles, it was proved false because it taught crazy things that contradicted the rest of scripture. Not to mention it was written hundreds of years after Jesus, claiming new information about Jesus.
5) Confirmed by Christ, prophets, or apostles.
For instance, we see in Luke 24:44 that Jesus confirms the 39 books of the OT as scripture.
6) Church usage and recognition.
This was actually one of the more weighty reasons for a book being recognized as Scripture. If a letter was being read and circulated among numerous Churches who were using that letter for preaching, discipleship, and church policy, it was very likely God-Breathed Scripture.
Therefore by using these six categories, the early Church was able to decide which books were God-Breathed Scripture, and which books or letters were not.
That means all 66 books in your Bible passed not one or two of these tests, but indeed they passed them all! Looking back, we can see the early Church went to great pains to make sure they got the Bible right.
So the next time you flip to your Table of Contents, know that those titles were once fought over, and God saw to it that they won!
(Six Criteria taken from Dr. Bruce Ware’s Systematic Theology I Class)