Gnosticism (gnosis) is not a single school, nor can it be assimilated to a doctrinal unit, although it is possible to identify certain lines common to all Gnostics. It is a philosophical and religious tendency that takes some elements of Platonism, Philo, Judaism and Christianity. It was developed mainly in Alexandria and Rome during the 2nd centuries AD. Orginal Gnostic literature has been lost and this production is only known through citations by authors who polemize and question Gnosticism.
The salvation of man is obtained by means of supreme knowledge (Gnosis), which is different and superior to “simple” faith.
For the Pythagorists, the Gnosis was a divine knowledge proper to the initiates. For the Gnostics, it was, it was the knowledge of men of higher nature, called pneumáticos or spiritual (who do not need redemption), compared to the inferior knowledge of material men (matter is what corrupts) and psychics (they need the redemption of Jesus, they are Christians).
Gnosis is a faith transformed into wisdom or higher knowledge. It is common next to this, to add the affirmation regarding the absolute transcendence of God to such an extent that I could not be the creator of the world (since he has no contact with it), let alone be the cause of evil .
They introduce between God and the world a series of “intermediate beings” until they reach the Demiurge creator of the sensible world (generally identified with the Old Testament God). Matter is the origin of evil and what corrupts.