Gnosticism was an early Christian heresy that favoured a secret knowledge (Greek: gnosis). This knowledge was that we are truly spirit. The emphasis of spirit over body comes from Platonic influence. This also led to a rejection of the Old Testament as that God created the material world, which Gnostics know to be evil. Mythicists often use later Gnostic writings against the earlier New Testament writings to attempt to show early Christianity supported their view.
A Christian Response by Stephen J. Bedard