Related: Church Heresies
Gnosticism. The word Gnostic comes from the Greek word ‘gnosis’, which means knowledge. The word is used by historians to describe a school of thought. Gnosticism arose from a group of evil workers who claimed to have higher light, special spiritual knowledge, or “secret wisdom”. This movement began in the days of the apostles, and continued into the 5th century. Before John died the seeds of Gnosticism had been sown; perhaps even before Paul's death. The roots of Gnosticism are addressed in Colossians, under the heads of rationalism and ritualism, two areas in which these false teachers were seeking to add something to Christ. Paul counters by saying "and ye are complete in him" (Col. 2:10). Paul speaks of the Gnostic system as "oppositions of false-named knowledge" (1 Tim. 6:20). John’s epistles are written to defend against the inroads of Gnosticism. He refers to the Gnostics as "the deceivers" (2 John 1:7), and those that "go forward and abide not in the doctrine of Christ" (2 John 1:9). Peter warns of their false teaching, and Jude warns of its moral effect on the Christian testimony.
The best description that historians had of Gnosticism until recent times came from Irenaeus' most important work 'Against Heresies' (A.D. 180), and the 'Seven Epistles' of Ignatius of Antioch. In 1945 the Nag Hammadi library in Egypt was discovered, which contained many Gnostic texts. From the sources we have, a composite profile of Gnostic theology can be assembled, although - like many systems of evil - not every Gnostic teach fit the full profile. This mystical system arose from both Jewish and Greek roots, but the Greek tendency to spiritualize and allegorize took over. Their view of the world was one of dualism: the spiritual world was good, and the material world was evil. The human soul therefore was a jewel trapped in a filthy body of matter. In this case, death is a great victory, at which time the soul is finally freed from the corrupted body, and therefore from the material world. Because of this, the Gnostics rejected the teaching of the bodily resurrection from the dead, which Paul preached. They also rejected the notion that the creation itself will one day be redeemed.
This dualism extended into their view of deity. Gnostics believed there were two gods: a higher god called the 'Monad' and a lesser, mischievous god called the 'Demiurge'. The Demiurge was equated with Jehovah of the Old Testament, and credited with creating the “evil world of matter”. The Demiurge, they said, played a cruel trick on mankind by trapping the soul in a material body. Rather than see sickness and pain as a result of man's sin, Gnosticism blamed it on creation. But this view had an even more serious result: it corrupted the doctrine concerning the Person of Christ. The incarnation was rejected, because it connected what was material (a human body) with what was divine. The Gnostics would try to separate “Jesus” from “Christ”. There were various heterodox positions on the Person of Christ, but most centered around the idea of an emanation: a shining out from a source. Christ, they taught, was an emanation from God. In some forms, the emanation (Christ) was united to a mere man named Jesus at his baptism, but returned to God before Jesus’ death on the cross. In other forms, Jesus was only an apparition; i.e. he appeared to be a physical man, but never actually was. It was even claimed by some that if Jesus were to walk across the sand, he would leave no footprints behind him when he walked. In either case, Gnosticism denied the full truth of the Person of Christ, that He was fully God (because an emanation is less than its source), and and fully man (because an emanation is not a man). In doing so, this evil system annulled the foundations of Christianity, including the incarnation, the atonement, and the resurrection. In their view, Christ was sent to make known the good 'Monad' of heaven, and to expose the mischievous 'Demiurge', and in so doing, to lead believers into the higher knowledge. It involves a great deal of mystical teaching, secret knowledge, and forged documents.
Fundamentally, the separation of the spiritual from the material resulted in two forms of practical evil. On one hand, it resulted in asceticism, the teaching that the body's needs should be denied because the body is evil, which led to an extreme form of legalism; "forbidding to marry, bidding to abstain from meats", etc. (1 Tim. 4:3). On the other hand, it resulted in lasciviousness, because if the body is evil, God is not concerned with the deeds done in the body. This is taken up in Jude, were the writer exposes the false brethren as "ungodly men, turning the grace of our God into lasciviousness, and denying the only Lord God, and our Lord Jesus Christ" (Jude 1:4). John writes in his first epistle, urging the necessity of practice. "My little children, let us not love in word, neither in tongue; but in deed and in truth" (1 John 3:18). The idea that theory can be separated from practice is connected with Gnostic doctrine. John gives various ways to know if someone is truly born of God, or if they are of the Devil. If they teach evil doctrine concerning the Person of Christ (1 John 2:22; 4:2-3; 2 John 1:7, 9), or if they consistently practice evil works (1 John 3:6,8,10,15; 4:20). John also encourages the saints that they were not like the Gnostic teachers, and they could know that they had eternal life (1 John 5:13).
The doctrine of the New Testament anticipates this irreverent and wicked system of teaching by stating the simple truth of Christ's Person and work. Many of the false cults today are, in a sense, a modern form of Gnosticism. When their error is pushed, it must be countered in the same simple way that apostles met the danger they faced centuries ago.