The Cathars:  Cathar Beliefs:  Vindication:  Gnosis

There are numerous references to gnosis in the New Testament, but we never notice them because they are translated away as mere knowledge rather than secret knowledge.  

Gnostic messages are are also explained away by theologians, sometimes by making them say the opposite of what they really say in the biblical text.   For example, why did Jesus speak in parables?   We are frequently told that he did so in order that all the simple people should understand his message.   Read the passage for yourself and you will see that the truth is exactly the opposite.   According to Jesus himself in all the synoptic gospels, he spoke in parables so that certain people would not understand him (Luke 8:9-10, Matthew 13:10-13 or Mark 4:10-12).  

Although there are others, this passage alone (if accurately recorded in the cannonical gospels) proves conclusively that at least part of Jesus's message was a gnostic.

There are of course, a whole library of gnostic gospels, once thought "lost" (ie suppressed by the mainstream Church), but preserved in the desert and rediscovered in the twentieth century. According to these gospels too, Jesus was a gnostic teacher.