Gnosticism starts out with a bloody nose, shoved out of the way, covered in dust, an unhappy loser in the battle to explain Christianity. It’s the theory about Jesus that didn’t win, but losing is the genius of gnosticism. Without it’s 2nd place finish it doesn’t exist. Gnosticism comes alive only because it believes that the crude layers of “counterfeit” Christianity must be peeled back to discover the truth.
Gnosticism is all about discovering hidden knowledge. What are some of the discoveries? The hidden truths about God and Jesus are many and varied, but there is a basic story line: The ultimate God is completely transcendent and unknowable, divine emanations proceed forth from him in the form lesser deities. Finally, the God of the Jews, A deity extremely low on the depth chart, discovers that he is powerful enough to create but stupid enough to see the foolishness of creating. The earth is born on the ill-advised whim of a lesser deity. The unpleasant business of matter has begun. The whole plan is a disaster from the beginning. Ultimately the human will need to escape the debacle that is the material world. Jesus factors into the escape plan but not as a human and not in any clear sense. Jesus is divine it is believed, and divinity can never merge with humanity. Jesus’ life on earth is mysterious, ghostly even — not human. He doesn’t do miracles or connect in earthy ways with humans as the four gospels suggest. He teaches secret things to special people. With resentment the gnostic faithful blamed ignorant Jews for founding a church with a Jesus that is both human and divine.
The Gnostic heresy officially lost. The Nicene creed of 325 A.D. was the certified repudiation of it, but it did not go extinct on the contrary strands of it’s influence pervaded the church and continue until this very day. Perhaps the most troublesome impact of gnostic heresy on Christianity was the notion that the soul is good and the body bad. Somehow in spite of official decree this dichotomy remained entrenched in Christian thought with horrible ramifications. For example, sex became a bad thing, because it was this very physical matter oriented act that created more living breathing matter, and matter was bad! The great church father Augustine remarked “nothing turns my thoughts towards darkness quicker then the caresses of a woman.” Women were the collateral damage of this belief system they were of less value because it was their charms that further spread the darkness. It’s no surprise that at the end of the gnostic gospel of Thomas we learn that women will not be allowed into heaven! Its was believed that a Christian businessman could never hope to be as spiritual as a priest or monk, a structure of value based on asceticism and denial of material pleasure began to shape an entire culture. If one enjoyed the simple pleasures of life too much, suspicious glances would be cast in their direction, material pleasure became a dirty thing.
Christians do not believe that the human is a good soul imprisoned in an evil body. A Christian should love his body and the pleasures that go with it because they are gifts from a good God. The human problem is not the body or the pleasures it affords. The problem is how the human manages to take God’s good gifts and pervert them or make idols out of them, choosing to love the gift more than the giver. This is where the real evil resides and why Jesus’ rescue mission had to happen.
By the way, since gnosticism believed matter was evil and the spirit was good, gnostics actually had two camps: the ascetics and the libertines. The ascetics said, The spirit is what really matters, so we must deny the body. The libertines said, The spirit is what really matters, so what we do with the body, including sensuality, just does not matter. Party on, dude!
But, as you pointed out, God created us with both a body and spirit, and we are to honor Him with both. The ascetic is wrong in that he does not understand that the body is a gift from God. The libertine is wrong in that He denies the purity that God commands for our good.