A common line in scholarship is about how stifling and intolerant the proto-orthodox churches were towards “other” Jesus literature and “other” forms of Christianity.
While the proto-orthodox churches very quickly venerated the four Gospels, this never seems to have meant restricting themselves to reading only the four Gospels. First, the papyri available from the second century attests the popularity of Matthew (P64 + 67 P103 P104), then John and Luke (P52 P75), in addition to an interest in other Jesus traditions given the residual remains of “other” Gospel fragments (P. Oxy 1 [Gos. Thom. 27] and P. Eg. 2 [Gospel-like materials]). Second, evidence of further openness to “other” Jesus traditions is attested by the presence of agrapha in proto-orthodox sources. Proto-orthodox Christians were interested in what Jesus said irrespective of the source where he said it. Third, the use of “free sayings” ‒ deriving from a mixture of memory, harmonization, and alternate traditions ‒ by proto-orthodox authors like Ignatius, Papias, Clement, Ps.-Clement, Justin, and the authors of the Epistula Apostolorum and the longer ending of Mark 16, prove that the proto-orthodox did not see themselves as living in a textual straight jacket, even while they argued for the apostolicity and integrity of their sacred texts. Fourth, and similar to the last point, the willingness of authors to cite “other” Gospels and their traditions, not polemically, but as anecdotal evidence about some point of interpretation or as a clarification to the events of Jesus’ life, suggests a serious openness to other Jesus literature when it is deemed illuminating to the author’s literary tasks. Justin refers to the tradition found in infancy Gospels about Jesus being born in a cave and the great light that shone around at his baptism found in the Diatessaron and the Gospel of the Ebionites. The Chronicler Hegesippus quoted from the Gospel according to the Hebrews and from a Syriac Gospel. Clement of Alexandria utlized the Gospel of the Egyptians and Gospel according to the Hebrews without any query as to their scriptural status. Later Origen, for all his polemic in his Luke homily against “other” Gospels, is quite comfortable citing non-canonical texts in his Gospel commentaries. Fifth, this openness to other Jesus Books was not restricted to Christian scribalism, but even extended to corporate worship. Bishop Serapion of Antioch in the AD 180s initially permitted the church at Rhossus to use the Gospel of Peter, but only later forbade it when it was deemed conductive to (not composed by) docetic teachers.Thus, one searches in vain for some kind of top down episcopal authority that excised the diversity of Christian literature in proto-orthodox churches in the second century.
 Cf. W.D. Stroker, Extracanonical Sayings of Jesus (Atlanta: Scholars, 1989); John K. Elliott, The Apocryphal New Testament (Oxford: Clarendon, 1993), 26-30; Bart Ehrman and Ziatko Pleše, The Apocryphal Gospels: Texts and Translations (Oxford: OUP, 2011), 351-67.
 Cf. Protevangelium of James 18‒19; Arabic Gospel of the Infancy 2‒3 with Justin, Dial. Tryph. 78; Tatian, Diat. 4.40; Gos. Eb. § 2 with Justin Dial. Tryph. 88.
 Eusebius, Hist. Eccl. 4.22.8.
 Cf. Ehrman and Pleše, Apocryphal Gospels, 218-19, 226-29.
 Origen cites the Gospel according to the Hebrews (Comm. Joh. 2.6) and the Gospel of Peter and the Protevangelium of James (Comm. Matt. 10.17).
 Eusebius, Hist. Eccl. 6.12.4.