Another important development during the period from AD 21 to 325 was the formation of the Bible. The Bible is a collection of many books. The collection as we have today, tells us along story of selection and limitation. The Church in the early years after the Apostles was aware of three authorities: the Scriptures, the spoken word of Christ and the oral testimony of the Apostles. For them any reference to scriptures meant only the Old Testament. In course of time the works and words of Christ recorded by the Apostles i.e. the Gospels were circulated among them. Gradually they began to assume prominence and were put on the same level with the Scriptures of the Old Testament. There were a good number of books circulated among the Christians which claimed Apostolic authority. So the church had to cautiously select and make a Canon of books (body of writings which are accepted as genuine, authoritative, and inspired by God) of the New Testament. This process of collection and canonization of the books of the New Testament was speeded up by several factors.
1. First among the factors that speeded up the formation of the New Testament Bible, was the Christian worship. In the Christian services it was customary, after the lessons from the Old Testament, to read any Apostolic letter. For example l Thessalonians was to be "read to all the brethren" (1 Thess. 5:27). After the Epistle to the Colossian had been read among them they were to hand over it to the Church of Laodicea and in turn receive another letter from Laodicea (Col.4: 16) The Epistles of Paul were widely circulated among the early Christian Churches. The first Epistle to Corinthians written by Clement of Rome (AD 100) was read in the Corinthian Church and was widely known in early church especially in the east. This book is included in the Orthodox Canon of the New Testament. But it is not found in the version of the Bible we commonly use today.
2. Another cause that led to the formation of a Canon of the Christian Scriptures was the growth of Christian literature. Christian writers used familiar words and phrases of the Apostolic writers and in some cases quoted them. This enhanced the canonization and made the process easier.
3. Thirdly, in the middle of the second century a Gnostic heretic called Marcion drew up his own list of sacred books. In the list he excluded the whole of Old Testament and accepted only a mutilated version of Luke and then of the Pauline epistles. The Church soon found it necessary to make a Canon of the New Testament.
4. In the second century different versions of the New Testament books were made in different languages. Syriac version was circulated in Syria, and Latin version in Africa. In the end of the third century and the beginning of the fourth century there produced a version in Sahidic dialect in upper Egypt. Those books so published formed the Canon of the New Testament in those regions.
The effort to fix the Canon was not coordinated. It differed from place to place. A Canon of the New Testament called the Muratorian Canon (l80-190) compiled in Italy was the earliest ecclesiastical list of the New Testament books. It listed 22 books. Irenaeus accepted 21 books as Canonical. Hippolytus of Rome (AD 235), a disciple of Irenaeus had 21 books of the New Testament in his list excluding Hebrews. The Syrian Canon had only 22 books excluding Revelations, 2 Peter, 2 John and Jude. Tertullian (200 AD), a Father of the African Church was the first one to use the, phrase "New Testament". In Alexandria, Athanasius (367) gave a list of 27 books, the same as we see in the common version of the Bible.
Thus the Canon of the New Testament came to be fixed by the different churches.