The Creation of the New Testament
The New Testament books were written in considerably less time than the books of the Old Testament. They were all written in Greek by the apostles of the first generation. Other books purporting to be written by the apostles but in fact were written by others in the second century were quickly recognized as non-apostolic and as the products of heretical groups living on the fringes of the apostolic church. These later books (such as the Gospel of Thomas, the Gospel of Peter, the Gospel of Judas) were never seriously considered by the Church as legitimately apostolic or true, or as possible candidates for reading in the liturgical assembly. These latter books were not so much “lost Gospels” (as is sometimes claimed), but “rejected Gospels,” for the Church had little trouble discerning their spurious nature.
The core of the New Testament collection was quickly recognized by the Church as belonging to its Tradition—i.e., the four Gospels of Matthew, Mark, Luke, and John; the Acts of the Apostles; and the letters of Paul. Other New Testament books took longer to gain universal acceptance—books like 2 Peter and the Revelation. But by the end of the 4th century, the Church by and large had reached a settled consensus about the twenty-seven books of the New Testament as we now have them.
This consensus was all the more secure because it was not the result of a single council or gathering of bishops, but the slow and evolving consensus reached gradually by everyone over space and time. For there was then no real method of enforcement of a settled and definitive list or canon; each bishop, as head of the church in his own city or village, decided for himself what would or would not be read at the liturgical assembly on Sunday. If a bishop decided to read (for example) the Apocalypse of Peter at the Liturgy, there was little that the bishop of the next village, who rejected the Apocalypse of Peter, could do about it, apart from remonstrating with his neighbour and saying he thought that his decision was wrong. And bishops did remonstrate and discuss and talk, and eventually a solid consensus emerged. This consensus was not the result of any single gathering (which conceivably could err), but the result of years and decades of discernment and debate— and therefore much more likely to represent a true consensus of the entire Church.