As we have seen, for a long time the consensus of scholarship has held that gnostic and other heretical groups held a virtual monopoly on the Fourth Gospel throughout much of the second century. Here again are Melvyn Hillmer's conclusions reached in 1966,
At a time in history when the Apologists were using John very sparingly, with only incidental citations, these gnostic writers were writing commentaries on the text. This seems to be clear indication that John was first fully accepted and used as authoritative in gnostic circles; not until Irenaeus does it have the same kind of position in other than gnostic writers. 1
The Commentaries of Ptolemaeus and Heracleon from the second generation of Valentinianism, give the earliest clear indication of the acceptance of the Gospel of John as canonical and worthy of verse by verse comment. The interpretation in these commentaries is in terms of Valentinian gnosticism but nevertheless demonstrates a final stage in the recognition of the gospel as a writing which has scriptural authority. It is significant that this position is first accorded to John in the work of Valentinian teachers, who were able with relative ease to interpret the Fourth Gospel in terms of their own theological system. 2
The more recent formulation of J.-D. Kaestli states,
1) On one side, we have underscored the lack of clear attestation of a use of the fourth gospel in the texts and with the authors who have been considered afterwards as the representatives of 'orthodox' Christianity. One must await the last quarter of the second century, with Irenaeus and Theophilus of Antioch, to find the first sure witnesses attesting to the full acceptance of John in the 'canon' of the Great Church.
2) On the other side, contrasting with this absence of attestation, we have recovered the place of choice which the gospel of John held with the gnostics of the Valentinian school, with Heracleon in particular. 3
In this section I shall not attempt to present an exhaustive, systematic examination of the borrowings from the Fourth Gospel in gnostic or gnostic-related literature from the second century. The task has to be more focused. First of all, just how much did the Valentinians and gnostics of the