Early canonical lists
The
Festal Letter of Athanasius from 367 AD contains the earliest known list of all 27 New Testament books, and only those books. But it is far from being the earliest canonical list.
Origen, writing over a century earlier around 250 AD in his typical metaphorical style, compared the apostles to priests blowing trumpets around Jericho to herald the Gospel. In the course of his fanciful description, he appears to cite all 27 books of the New Testament, with the possible exception of Revelation.
The
Muratorian Fragment, dated to about 180 AD, is the earliest known canonical list of New Testament books, affirming 22 of the 27. These include the four Gospels, Acts, all 13 of Paul’s letters, Jude, 1 John, 2 John (and possibly 3 John) and Revelation.
Even earlier witnesses to the authority and canonicity of the Gospels include
Papias (c. 125 AD) a disciple of John; Justin Martyr (c. 150 AD) who wrote of the Gospels “drawn up by [Jesus’] apostles (Matthew, John) and those who followed them (Mark, Luke)”; and his pupil Tatian’s
Diatessaron (c. 170 AD), one of the earliest harmonies of the four Gospels.
Irenaeus, writing around 180 AD and contemporary with the
Muratorian Fragment, stated that there could be no more and no less than four Gospels, just as there are four winds and four corners of the earth.
Finally, one of the most useful keys to understand how the canon developed was provided by the church historian Eusebius in the early 4th century. He laid out four categories of books that were available in the early church, in descending order of value:
Recognized books had been universally accepted since earliest times and there had never been any serious dispute over them. These include 22 of the 27 New Testament books: the four Gospels, Acts, Paul’s 13 letters (plus Hebrews), 1 John, 1 Peter and Revelation.
Disputed books had been subject to some early debate but were still considered canonical. These are the five shorter NT books: James, Jude, 2 Peter, 2 John and 3 John. Together, these first two categories make up the canon of the New Testament.
https://www.focusonthefamily.ca/content/the-new-testament-canon-why-these-27-documents