The earliest text about Cerinthus places him alongside Simon Magus as "false apostles" and enemies of Christ and the twelve apostles (the Epistula Apostolorum 1, 7; cf. Acts 8:9-24). We also get an amusing anecdote that may have been passed down by the bishop Polycarp of Smyrna, the teaching of Irenaeus of Lyon, about how the Apostle John once confronted Cerinthus in a public bathhouse in Asia Minor and fled for his life thinking that God would strike down the walls because the "enemy of the truth" was inside the building (Irenaeus, Against Heresies 3.3.4). What was so bad about Cerinthus?

We have three different portraits about Cerinthus’s teachings. According to Irenaeus (Against Heresies 1.26.1), Cerinthus taught that the material universe was created by a lesser divine power rather than the supreme God. This was a way of protecting God, a completely spiritual and transcendent being, from direct involvement in the act of creation. Later theologians who depended on Irenaeus specify that Cerinthus taught that the world was created by angels, or that the creator god was a chief angel, and that angels gave the Law. As for Cerinthus’s Christology, he accepted that Jesus was an ordinary human and the biological son of Joseph and Mary. However, since Jesus exceeded his peers in righteousness and wisdom, he was possessed by a divine entity called "Christ" at his baptism, which enabled him to teach about the unknown Father and perform miracles. Since this divine entity was impassible and could not suffer, the Christ aeon left Jesus before his crucifixion and resurrection.

The second portrait of Cerinthus is that he taught about the thousand year reign of Jesus from Jerusalem and pictured it as a great wedding festival. This belief, known as chiliasm or millenarianism, is based on a literal interpretation of Revelation 20:1-6. Gaius of Rome and Dionysius of Alexandria exaggerated the physical, sensuous pleasures of Cerinthus’s millennial kingdom which involved feasting, marrying, and sacrifices (cf. (in Eusebius, Ecclesiastical History 3.28.2; 7.25.3). There was even the charge that Cerinthus forged the book of Revelation in the name of the Apostle John. Gaius accepted the charge because he despised the book of Revelation and the Montanists who promoted it. Dionysius allowed that some holy person named John wrote the book of Revelation, but he insisted that this John was not an apostle and that the book must be interpreted allegorically (7.25). Others charged Cerinthus with forging both the Apocalypse and the Gospel of John (cf. Epiphanius, Panarion 51.3.6; Dionysius bar Salibi, preface to his Commentary on the Apocalypse).

The fourth-century heresiologist Epiphanius of Salamis offers a third portrait of Cerinthus. Influenced by the link that Irenaeus draws between the beliefs about Jesus held by Cerinthus and another Jewish Christian sect (Against Heresies 1.26.2), Epiphanius paints a picture of Cerinthus as a full-fledged Judaizer involved in every dispute about whether all Christ-followers must obey the Torah (including circumcision for males) in the New Testament (Panarion 28.2.3-5.3). He also associates Cerinthus with Paul’s opponents in Corinth who denied Christ’s resurrection before the general resurrection of everyone from the dead (28.6.1-3). Based on medieval Syriac evidence (cf. Dionysius bar Salibi), some scholars believe that Epiphanius’s source was Hippolytus of Rome in the third century. Others argue that Epiphanius was the one who invented this portrait of Cerinthus, which influenced subsequent Christian writers.

So who was Cerinthus? Although older modern scholarship saw him as an exemplar of Jewish Gnosticism, there is no solid evidence that Cerinthus was ethnically Jewish. The main divide is between scholars who view Cerinthus as a Gnostic, arguing that the physical world was created by an inferior demiurge or "craftsman" and that a spiritual emissary called Christ came to reveal saving knowledge, or think that Cerinthus just held to a more primitive Christology and eschatology, namely that Jesus was the human Messiah who will rule over a millennial kingdom on earth. Some scholars have tried to reconcile the first two portraits. C. E. Hill argues that Cerinthus identified the demiurge with the God of Israel and believed that the demiurge would fulfil all the messianic prophecies in the Hebrew Bible during the millennium, but those who accepted Jesus’s message about the previously unknown heavenly Father would receive a spiritual form of salvation (i.e. Christians would not have a share in the millennium). I have argued that Cerinthus understood the supreme God and the demiurge to be on the same team, so that it was the former’s will that the latter would create the world and restore it into a paradise during the millennium (i.e. Christians would both experience life during the millennium and inherit their everlasting spiritual salvation after it was completed). For further engagement with the scholarly sources on Cerinthus, see my article www.cdamm.org/articles/cerinthus.