...The canon of the New Testament began to be more firmly established in the later 4th century.
One of the first synods met together to judge which books were to be read aloud in churches was the Synod of Laodicea, held about 363 CE. The decrees issued by the thirty or so clerics attending were called 'canons' Canon 59 decreed that only canonical books should be read, but no list was appended in the Latin and Syriac manuscripts recording the decrees. The list of canonical books sometimes attributed to the Synod of Laodicea is a later addition, most scholars agree.
The first complete listing of canonical books in the Denziger
Sources of Catholic Dogma is in §84, which dates from A.D. 382. The third Synod of Carthage, in 397 CE ratified the canon accepted previously at the Synod of Hippo Regius in North Africa, 393 CE, the acts of which have been lost. This synod marks the beginning of a more widely recognized canon. The inclusion of some books in the
New Testament was debated:
Epistle to Hebrews,
James,
2 John,
3 John,
2 Peter,
Jude and
Revelation. Grounds for debate included the question of authorship of these books; suitability for use; and how widely they were actually being used. 2 Peter is the most weakly attested of all the books in the Christian canon. One concern regarding the
book of Revelation at that time is that it was already being interpreted in a wide variety of controversial ways. Virtually all Christians have accepted and continue to accept the same 27 books as the New Testament, except for those Syriac-speaking Christians who continue to use the Peshitta...