The books in the New Testament were all written before the end of the first century (before AD 100)
Before long, however, other Christian writings were created by people. But these writings did not carry the same apostolic authority. Some of them even contained teachings that we different to what the apostles had taught ie like the gnostic gospels etc
In order to protect the early Christians from false teaching after the death of all the apostles, the early leaders clairified and delineated the apostolic writings
By AD 170 the concept of the New Testament Canon was firmly established, and the main contents were set in place,or around this time,i cant find the actual date
There were three main criteria by which early Christians recognized the authoritative books that had established the church and were to be the measure or standard of the Christian faith:[5]
The book had to be written by apostolic authors (or those who were closely associated with apostles)
The book taught the orthodox faith of the apostles, and
The book had been widely accepted in earliest churches from the beginning
As the early church clarified the final list of authoritative books, they tested that the church itself had been established by the words and works of Jesus as communicated by the apostles (Eph. 2:20)
The written works associated with the apostles are the objective norm by which all teachings, all churches, and all leaders are to measure and evaluate themselves.[6]
What gave the New Testament canon its authority is that it contained the teachings of Jesus given through his apostles or those closely associated with the apostles
Those teachings created the church.
Then, between AD 250 and 367, the leaders of the church at that time met in councils to officially recognize the books that had been and were to continue to be the authoritative words of the apostles
They settled upon the twenty-seven books of the New Testament
