The process for recognizing the 27 books of the New Testament began in the first centuries of the Christian church. Very early, the New Testament books were recognized as inspired by God. Clement of Rome mentioned at least eight New Testament books by 95 AD, and Polycarp, a disciple of John, acknowledged 15 books of the New Testament by 108 AD.
The first canon (meaning, “rule” or “measuring stick” in Greek) was the Muratorian Canon, which was compiled in 170 AD. The Muratorian Canon included all of the New Testament books except Hebrews, James, and the Letter of 3rd John.
In 363 AD, a church council meeting in Laodicea confirmed that the New Testament consisted of the 27 books that we see in our Bibles today. The Councils of Hippo in 393 and Carthage in 397 reaffirmed the same 27 books as authoritative.
It is important to understand that these councils didn’t choose the books in the New Testament; they simply recognized what the early church had always believed about the books. This was the end of a process, assuring these were the God-inspired books that the church was founded upon.
There were four principles used by the councils to determine whether a New Testament book was truly inspired by God. First, the author needed to be an apostle or have a close connection to an apostle. Second, the book needed to be widely accepted by the early church. Third, the book had to contain consistency of Christian teaching. Fourth, the book had to bear evidence of high moral and spiritual values that would reflect a work of God.