Did the Gnostics have the truth about Jesus? Their second century opponent Irenaeus would say that they did not. However over the last century a debate has opened up suggesting that the Gnostics provide a source of truth that is at least equal to the New Testament.
This question is of great importance when you consider the substantive difference between the beliefs of orthodox and Gnostic Christianity. This is best exemplified by contrasting the traditional teaching that Jesus physically died and rose again in order to make atonement for sin with the following quotation from The Apocalypse of Peter.
He whom you saw on the three, glad and laughing, this is the living Jesus. But this one into whose hands and feet they drive the nails is his fleshly part, which is the substitute being put to shame, the one who came into being in his likeness.
This disparity is crucial to our understanding of what it means to be a follower of Jesus and whether or not it is possible to receive forgiveness for sins and eternal life through Him. We will therefore be evaluating the arguments both for and against the thesis that the Gnostics had the Truth of Jesus. We will consider the arguments in favour first and then those against.
The first argument in favour of the Gnostics is that of geographical diversity. Walter Bauer takes the example of Egypt. Alexandria was an important city there and you would expect a thriving Christian community. However he finds no documentary evidence of orthodox Christians. The silence lasts up until the end of the 2nd Century when the prominent figures to emerge are heretical, for example Valentinus and Basileides. Bauer asks why the church would have been quiet about its origins in a place as important as Alexandria. His conclusion was that at least in certain geographical locations, early Christianity was heterodox in form and probably Gnostic.
The second argument in favour of Gnostic truth is that the New Testament itself highlights diversity in the early Christian Community. Koester tells us that “The term canonical loses its normative relevance when the New Testament books themselves emerge as a deliberate collection of writings representing various divergent convictions which are not easily reconciled with each other.”  Evidence for this diversity might be suggested from the argument over Jewish-Gentile integration that Paul records in Galatians 2. This demonstrates tensions between different apostles and their followers over how to handle practical issues with strong underlying theological implications.
The third argument is a development from the second. If the early church tolerated textual diversity, then this gives validity to the texts that the Gnostics themselves used which did not find their way into the New Testament canon. In 1945 a collection of manuscripts were discovered at Nag Hammadi, Egypt and have been identified as Gnostic texts. It is generally agreed that most of these documents were originally written in the second century AD. Although they often employ Jesus as a narrator, they are less concerned with his life and ministry and more concerned with using him as a mouthpiece for specific Gnostic traditions such as their alternative account of creation.
One stands out: The Gospel of Thomas. Thomas is a collection of dialogues between “The Living Jesus” and his disciples. It stands out for two reasons. Firstly it does show an interest in the person of Jesus to the point that there is significant overlap with material from the canonical gospels. Secondly, whilst accepting the Nag Hammadi copy as a late redaction, a number of scholars have been prepared to claim an early dating for the original text on which it is based. So for example Koester claims that, “in its most original form it may well date from the first century.” He argues that Thomas is comparable with Q.We will therefore evaluate the claims of the Gnostic writings to having the truth by engaging specifically with Thomas.
It is important to note that the argument is not about whether Thomas is older and so more reliable than the canonical texts. Indeed, although much source and form criticism has been carried out on both, conclusions on priority seem to be hard to ascertain. So whilst some scholars believe that ““occasionally [Thomas] seems to be the superior,” this is not always the case. Montefiore identifies an example of embellishment on the part of Thomas when, in the parable of the wedding guests, the number of excuses rises from three in Matthew to four in Thomas. Montefiore notes that, “triplets are more common than doublets in Jewish writing.” 
The argument then is that both sets of text are interpretative redactions of earlier sources. One source, Thomas, portrays Jesus as a teacher of wisdom, offering a collection of dialogues with very little narrative. In that respect it may be seen as closest to the original sources working on the assumption that Q, one of the supposed sources is believed to have taken that form. The lateness of the canonical gospels can be seen in their development of allegorical and especially apocalyptic explanations of the teachings of Jesus. If Thomas and the canonicals are both late interpretations of the message of Jesus, both based on equally valid ancient sources, then the Twenty-first Century reader is free to determine for himself which offers the best source of truth and his criteria will be which offers the best fit with a twenty-first century worldview.
We will now consider the response to the arguments in favour of the Gnostics possessing the truth about Jesus. Here then is the case for saying that they did not have the truth.
In response to the first argument that Egypt fails to provide any evidence of orthodox Christianity during the first two centuries, it has been noted that a number of alternative explanations can be provided for this. Thomas Robinson suggests that Egypt was simply not an important centre of early Christianity. Furthermore, Bauer doesn’t allow for other events that might account for the loss of important written evidence, such as the destruction of the Jewish community at Alexandria during the Jewish Wars (115-117). The problem is that Bauer’s argument is essentially based on silence. It isn’t one that can actually be proven.
In response to the second argument that the New Testament itself allows for a diversity of views about Jesus, we might note the consistent references in it to false teaching. The New Testament writers were united in identifying a common approach to Jesus so that whilst there may be differences in style, they are preaching the same gospel. This view of an orthodox church united around all the Apostles is supported by the fact that the Church in the second century had a strong understanding of this both through written and oral tradition. Irenaeus argues that the Gnostics are contradicted by Scripture and tradition and comments on tradition that; “we are able to recount those whom the Apostles appointed to be Bishops in the churches and their successors quite down to our time; who neither taught nor knew any such thing as they fondly devise.”He goes on to list those people including Clement and Polycarp who had been taught by the Apostles and were responsible for passing the truth on to the church in his day. That teaching occurred publicly and it would have been possible for others to controvert it if evidence existed that it was false. The argument is similar to Paul’s in 1 Corinthians 15.
The third argument in favour of Gnostic Truth was that the Gnostics had, especially in the case of the Gospel of Thomas, a text that carried equal validity in regards to authenticity with the canonical gospels. As we have noted above, the assumption has been that allegorical and apocalyptic elements indicate a later dating of a document whereas a simple collection of sayings is seen to be closer to the original sources. However, as N.T. Wright argues, it is this very presence of narrative, explanation and eschatology that provides the canonicals with the authenticity that Thomas lacks. The Judaism that Jesus and his followers enter into is very much a narrative and eschatological based religion. A writer wanting to introduce a significant character into Jewish religious life would have therefore have wanted to portray their life story and show how it fitted into Jewish history and Jewish prophecy.
With the Gospel of Thomas, the reader is left wondering who these people are, why they are talking and in what sense they might be important or relevant. The dialogues only make sense when placed within the story. Indeed, some of the narratives only make sense within the context of a later story of the church rather than in the context of the life of Jesus. For example, Sayings 12 and 13 support the leadership claims of James and Thomas within the early church. If Thomas was written earlier than the canonicals then you would expect a clear response from the New Testament writers demonstrating the prior claim of their chosen leaders. However, the nearest one gets to this is Matthew 16:13-28, the canonical equivalent of Saying 13. Although this passage has been used as a proof text for Peter’s leadership within the Church, even Koester acknowledges that this was a later response and not Matthew’s intention. Indeed whilst Peter is credited for declaring the truth about Jesus, he is also rebuked within the same passage. Where Thomas openly discusses the leadership succession from Jesus, the canonicals are ambivalent, Jesus instead warning of martyrdom and encouraging a servant attitude.
The argument in favour of answering our original question positively is based then, on a pessimistic view of historical research. In effect it says that we cannot get back to an agreed portrait of the historical Jesus. Within that environment, all portraits of Jesus become acceptable and valid interpretations. It is not only that we must answer the question “did the Gnostics have the truth?” We must also answer the question “what is Truth?” It seems to me however that we have two portraits of Jesus that it is possible to adjudicate between. The first one is of an esoteric teacher with no attachment to time or place in history, the other of a Jesus who sits firmly within the known context of Second Temple Judaism. This second account stands out as the more authentic; it fits in with what we know about the history of the time. Of course, it would be possible to develop a story that fits the First Century setting at any point within the next couple of centuries, especially in response to the destruction of Jerusalem and the Jewish Wars that heightened a sense of Apocalypse. This objection would be best met by a detailed evaluation of the canonical gospels in order to establish a sensible dating for them. Space does not permit such a study in this essay, however substantial literature is available supporting an early dating for the New Testament Documents.
We have seen that the argument in favour of the Gnostics having the truth about Jesus is based on the idea that earliest Christianity was diverse in nature so that the Gnostics had at least an equal claim to truth with Orthodox Christians. However, the propositions supporting this argument have been tested and found wanting. The argument that non-orthodox communities dominated in certain areas is based on silence. The New Testament does not provide a diverse collection of documents but rather a unified presentation of early church beliefs that specifically excludes alternative viewpoints. Finally, the Gospel of Thomas as a representative Gnostic Text compares unfavourably with the New Testament texts as an authentic portrayal of the historical Jesus. Therefore, it is the New Testament, and not the Gnostics, that we should turn to for the truth about Him.
Bauer, Walter. Orthodoxy and heresy in Earliest Christianity Philadelphia.: Fortress, 1971
Five Books of Irenaeus Bishop of Lyons Against Heresies Translated by The Rev. John Keeble, London.: A D Innes and Co
Logan, Alistair H B. Gnostic Truth and Christian Heresy, A Study in the History of Gnosticism Edinburgh.: T&T Clark, 1996
Koester, H. Gnomai Diaphorai: “The Origin and Nature of Diversification in the History of Early Christianity.” PP114-157 in Trajectories Through Early Christianity, dited by J.M. Robinson and H. Koester, Philadelphia.: Fortress, 1971
McKechnie, P. The First Christian Centuries, Leicester.: Apollos, 2001;
Marshall, I H. “Orthodoxy and Heresy in Earlier Christianity” Themelios 2 (1976-77): 5-14
Montefiore, Hugh., and Turner, H E W. Thomas and the Evangelists, London, SCM Press Limited, 1962
Pagels, Elaine. The Gnostic Gospels, 1979, London, Pelican Books, 1990
Pearson, Birger A. Gnosticism and Christianity in Roman and Coptic Egypt, New York.: T&T Clark, 2004
Robinson, Thomas A. The Bauer Thesis Examined, The Geography of Heresey in the Early Christian Church The Edwin Mellen Press, 1988
The Gospel of Thomas Annotated and Explained, Translated and Annotated by Stevan Davies, Woodstock.: Vermont, 2002
The Nag Hammadi Library Revised Edition, edited by J M Robinson, E.J Brill, 1988
Thomas at the Crossroads, Essays on the Gospel of Thomas Edited by Risto Uro, Edinburgh.: T&T Clark, 1988
Wright, Nicholas Thomas. Judas and the Gospel of Jesus, London, Society for the Promotion of Christian Knowledge, 2006
 Whilst I recognise that there has been significant discussion about the suitability of such a classification, for this essay I will follow the majority of the texts consulted in my bibliography in assuming that it is appropriate to talk about the Gnostics as a grouping united by specific beliefs in salvation through secret knowledge and alternative theories about the Creation of the Universe through a rebellious demiurge
 See generally Irenaeus, Five Books of Irenaeus Bishop of Lyons Against Heresies (Trans. The Rev. John Keeble London.: A D Innes and Co)
 See E.g. Elaine Pagels, The Gnostic Gospels, (Random House Inc, 1979; rep, London Pelican Books, 1990)
 The Apocalypse of Peter, in The Nag Hammadi Library Revised Edition, (ed J M Robinson, E.J Brill, rev, 1988), 377
 Bauer, Walter. Orthodoxy and heresy in Earliest Christianity (Philadelphia.: Fortress, 1971), 45. also cited in Birger A. Pearson, Gnosticism and Christianity in Roman and Coptic Egypt, (New York.: T&T Clark, 2004), 13
 H. Koester. “Gnomai Diaphorai: The Origin and Nature of Diversification in the History of Early Christianity,” in Trajectories Through Early Christianity, (ed. J.M. Robinson and H. Koester, Philadelphia.: Fortress, 1971), 114
 Koester, “Gnomai Diaphorai,” 121
 See E.g. The Apocryphon of John, in in The Nag Hammadi Library Revised Edition, (ed J M Robinson, E.J Brill, rev, 1988), 104-123
 The Gospel of Thomas Annotated and Explained (Translated and Annotated by Stevan Davies, Woodstock.: Vermont), 2002, 3
 Montefiore, Hugh., and Turner, H E W. Thomas and the Evangelists (London, SCM Press Limited, 1962
 H. Koester in his introductory comments to the Gospel of Thomas, in The Nag Hammadi Library Revised Edition, (ed J M Robinson, E.J Brill, rev, 1988), 125
 Koester in Nag Hammadi, 125
 Montefiore, cited in Koester, “Gnomai Diaphorai, 132
 Montefiore and Turner, Thomas and the Evangelists, 48
 See Stevan Davies, About the Gospel of Thomas, which provides an introduction to his translation, Gospel of Thomas, ix-xiv
 Robinson, Thomas A. The Bauer Thesis Examined, The Geography of Heresy in the Early Christian Church (The Edwin Mellen Press, 1988), 42
 Modrzejewski , cited in Pearson, Gnosticism and Christianity in Roman and Coptic Egypt, 15
 I. Howard Marshall. “Orthodoxy and Heresy in Earlier Christianity” Themelios 2 (1976-77): 5-14, 7
 Irenaeus, Against Heresies, Bk3 Ch II s2, 206
 Irenaeus, Against Heresies, Bk3, Ch III, s1, 206
 Irenaeus, Against Heresies, Bk3, Ch III, s3, 207
 Irenaeus, Against Heresies, Bk3, Ch III, s4, 208
 Irenaeus, Against Heresies, Bk3, Ch III, s3, 207
 Wright, Nicholas Thomas. Judas and the Gospel of Jesus, (London, Society for the Promotion of Christian Knowledge, 2006), 28
 See E.g. Daniel, Zechariah
 Gospel of Thomas, 13
 Gospel of Thomas, 15
 Koester, “Gnomai Diaphorai,” 123
 See E.g Matthew 16:24, John 13:14-15
 See E.g. Marshall, “Orthodoxy and Heresy in Earlier Christianity,”