The word “gnosticism” comes from gnosis, Greek for  “knowledge.” Esoteric or secret knowledge is meant. The Gnostics believed that only an elite few enjoyed special enlightenment. The Gnostic view of matter had profound implications: matter is evil. In their minds, true spirituality rose above the material world. Thus the god who made the material world (the god of the OT) is an inferior being. There are many gods, and many levels of spirituality. Gnosticism had two principal varieties: “ascetic” and “libertine.” The ascetic strain advocated harsh treatment of the body, since flesh was evil. The libertine strain held that what you did to your body was irrelevant.

Andrew Kitchen (Sydney, 1998) wrote the following summary, which I believe you will find helpful.

In a nutshell:

GNOSTIC =
*
Good and evil gods
* Non-humanity of Christ
* Old Testament rejected
* Salvation by knowledge
* Trinity denied
* Irenaeus opposed
* Creation is evil

Gnosticism is not a movement; there is no unifying cause. It is more like a variety of movements, each one offering some way of enlightenment prescribed by a guru, or philosopher with the gnosis (knowledge) of the way of life:

  • Idea of "special knowledge" of a spiritual world.
  • Accepted the ideas of salvation, supreme deity, heavenly beings at work in the universe.
  • These common beliefs help explain why Gnosticism lingered around the edge of the church for so long.
  • Gnostics considered Christianity to be very "materialistic".
  • Basic belief of gnosticism: Dualism - two cosmic forces - good and evil.
  • Evil identified with matter. Therefore the OT Creator God was evil. The Gnostic supreme being was far removed from such tendency to "evil".
  • Creation explained by a series of emanations. Eg God like the sun, and sunbeams emanate from him, an extension of his own nature, yet distinct.
    • These supernatural powers could produce inferior powers, until a long chain of divine creatures were produces, each weaker than its parent.
    • Finally, one was created that while powerful enough to create was silly enough not to see that creation is wrong. This was the God of this world, the god of the Jews.
  • Gnostics believed that somehow the pure light of heaven had become involved with the soul of man, therefore man had to be redeemed.
  • Christ then was a subordinate power to the Ultimate Deity sent to free men from te chain of matter. However, Christ could have no real contact with matter, so the Christ descended into Jesus at or around his baptism, and left before the passion and crucifixion. (Ebionite view).
  • Other arguments:
    • Docetism (from dokein, "to seem"): Jesus did not really have a body at all, he only seemed to be. Could not accept that Christ was human. Dilemma of a human saviour.
    • Spiritual classes: lower class lived by faith, upper class ( illuminated, or the perfect), lived by knowledge. Also, a spiritually disadvantaged group were not capable of "gnosis" under any circumstances. 

Dangers:

  • Jesus interpreted in light of the fascinating ideas of the enlightened men of the day. (cf evolution in 19th C).
  • If gnosticism had triumphed, Christians would have rejected their Jewish heritage.
  • Very difficult to combat as Gnostics held they had some secret information denied to their opponents. Either they had been given secret information that had been denied to the Jews, or else they had received some special revelation denied to their opponent.
  • Christians rose up to defend the faith: led to formation of Creeds. Eg. Apostle's creed (appeared first as a baptismal confession in 2nd C. Rome). Affirms a creator God, virgin birth, death, burial and resurrection of Christ, Resurrection of the flesh (ie not a good soul and an evil body).
  • Two strands:
    • Libertines -- salvation depends solely on knowledge, flesh counts for nothing, therefore it doe not matter how you live your life. Very licentious.
    • Ascetics -- flesh counts for nothing, deny it totally ' radically ascetic. 

Biblical Passages aimed at Gnosticism:

  • Col 1:15- Jesus - image of the invisible God, by whom all things were created.
  • Col 1:19 God pleased for all his fullness to dwell in Christ, and through him to reconcile to himself, all things, whether things on earth, or things in heaven.
  • Col 1:22 Reconciled you by Christ's physical body.
  • Col 2:4 Mystery of God, namely Christ in whom are hidden all the treasures of wisdom and knowledge. I tell you this so that no-one can deceive you by fine-sounding arguments.
  • Col 2:8 See to it that no-one takes you captive thorugh hollow and empty philosophy which depends on human tradition and the basic principle of the world. rather than on Christ.
  • Col 2:9 For in Christ, all the fullness of deity lives in bodily form.
  • Col 2:17-23 False humility, angel worship.
    • If you died to the basic principles of the world, why as though you still belonged to it submit to its rules: Do not handle! Do not taste! Do not touch!
    • Based on human commands and teachings.
    • Appearance of wisdom, but lack any value. 

Writings:

  • References in writings of Irenaeus, Hippolytus, Origen, Tertullian, Epiphanius -- some gnostic extracts but mostly counter-arguments.
  • Gnostic groups of the 2nd and 3rd centuries include the Cerinthians, Sethians, Ophites, Basilidians, Marcellians, Carpocratians, Marcosians, Simonians, and Valentinians. This last group were closest to Catholic christianity in their doctrine.
  • Gnostic Documents
    • Codex Askewianus containing the Pistis Sophia
    • Codex Brucanius containg the books of Jeu
    • Codex Berolensis containing Gospel of Mary, Wisdom of Jesus, Acts of Peter, Apocryphon of John.
    • All in Coptic. Discovered 1945 -- collection of about 50 documents found at Nag Hammadi in Upper Egypt.
    • Writings of Valentinus.

Leaders:

  • Simon the Sorceror - claimed divinity and salvation through knowledge of him rather than God. Early Christian writers universally regarded him as the fount of all heresies.
  • Menander - believe in me. Antioch end of first C.
  • Cerinthus - the Christ descended on Jesus and departed before the crucifixion. John fled the bath-house when Cerinthus was there - Irenaeus.
  • Marcion (not a Gnostic, but some common ground):
    • Arrived in Rome in 140AD
    • Saw God of the OT as being vengeful, unknowable and unloving, v. God of NT who is loving and gracious.
    • Rejected humanity of Jesus and the resurrection of the body. Jesus appeared in AD 29 in Capernaum -- i.e., no virgin birth.
    • Rejected idea of the resurrection of the body.
    • Rejected OT totally. Retained 10 of Paul's letters, and a mutilated version of Luke. Rejected "Jewish" books such as Matthew, Hebrews, Mark, Acts. Believed that Paul was the only apostle who did not corrupt the gospel of Jesus.
    • Marcionites set up own churches. No wine at communion.
    • Ideas spread to other Gnostic Sects and influenced by other sects. Spread to Italy, Armenia, Arabia.
  • Valentinus - Alexandria, came to Rome in 140. 

Sects:

  • Manichaeans - Mani (216-76), Mesopotamian born Persian. Dualistic religion, zealous missionary.
  • Mandean communities today in Iraq and Iran are the sole surviving remnants of Gnosticism. 
  • Libertines. 

Opponents:

  • Irenaeus - disciple of Polycarp. Bishop of Lyon in 177. Two major works: Against Heresies and Proof of the Apostolic Preaching.
  • Tertullian - Against Marcion 207
  • Justin Martyr 

Modern Era:

  • Psychologist Carl Jung picked up the Nag Hammadi writings discovered in the 1940s and applied gnostic principles to psychology.
  • New Age Teaching reminiscent of Gnostic principles.