Development of the New Testament canon writers. (Books not attributed to these three are: Matthew, Mark, Luke, Acts, James, and Jude. The authorship of Hebrews has long been disputed.) Many modern Protestants point to four "Criteria for Canonicity" to justify the books that have been included in the Old and New Testament, which are judged to have satisfied the following: The basic factor for recognizing a book's canonicity for the New Testament was divine inspiration, and the chief test for this was apostolicity. The term "apostolic" as used for the test of canonicity does not necessarily mean apostolic authorship or derivation, but rather "apostolic authority". "Apostolic
Development of the New Testament canon on the left side; they four also had the face of an eagle"—equivalent to the "four-formed" gospel, is the origin of the conventional symbols of the Evangelists: lion (Mark), ox (Luke), eagle (John), man (Matthew). Irenaeus was ultimately successful in declaring that the four gospels collectively, and exclusively these four, contained the truth. By reading each gospel in light of the others, Irenaeus made of "John" a lens through which to read "Matthew", "Mark" and "Luke". Based on the arguments Irenaeus made in support of only four authentic gospels, some interpreters deduce that the "fourfold Gospel" must have still been