Most of us have heard of Gnosticism. Until recently I had assumed that it was strictly an early Christian heresy. Evidently it was a much broader philosophical movement that swept across the entire ancient Roman world. Harold O. J. Brown comments in his book:

"What seems to be the case is that when the gnostic movement encountered Christianity, several of its major teachers adopted and adapted a number of basic New Testament ideas to their gnostic mentality and then sought to propagate the resulting synthesis among Christians and non-Christians alike." [HERESIES; pg. 48]

Commentators believe Paul had Gnosticism in mind when he wrote:

"Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ." Colossians 2:8

"O Timothy, keep that which is committed to thy trust, avoiding profane and vain babblings, and oppositions of science falsely so called: Which some professing have erred concerning the faith. Grace be with thee. Amen." 1 Timothy 6:20, 21

In the latter passage the word "science" is from the Greek word gnosis. This is the root of the word "gnosticism" which, says Paul, is a "false knowledge" and is not only deceptive but also at odds with "the faith once delivered to the saints."

It's well documented that Docetism, the first heresy within Christianity involving Christology, was a product of Gnostic teachers. More information about Gnosticism is appended below; it is from Harper's Bible Dictionary.

Gnosticism, a generic term for a variety of religious movements of the first centuries of the Christian era. Although the theology, ritual practice, and ethics of these groups differed considerably, all purported to offer salvation from the oppressive bonds of material existence through gnoµsis, or ’knowledge.’ Such knowledge was diverse, although it regularly dealt with the intimate relationship of the self to the transcendent source of all being, and this knowledge was often conveyed by a revealer figure.

What is known about Gnosticism traditionally depended upon reports in the church fathers such as Irenaeus, Hippolytus, Tertullian, Origen, and Epiphanius, who were opponents of Christian Gnostic teachers. Since the eighteenth century, several original Gnostic works have been discovered, including Codex Askew, Codex Bruce, the Berlin Gnostic Codes and, most recently, the Nag Hammadi collection.

The relationship between Gnosticism and early Christianity has been a controversial issue. Against the patristic view that Gnosticism was a Christian heresy begun by Simon Magus, many modern scholars have held that it was originally an independent movement. Earlier expressions of this opinion, which posited at the core of Gnosticism a redeemed-redeemer myth of possible Iranian origin, have proven questionable. Primarily on the basis of the Nag Hammadi evidence, many today hold that Gnosticism first emerged in the late Hellenistic or early Imperial period among speculative and syncretistic Jews.

By the second century, Gnosticism achieved its classical form among both Christian and non-Christian exponents. One example is found in the teachings of the Valentinians, Christian Gnostics who held that the world emerged from a primordial pair, or ’syzygy,’ Depth and Silence, from which emanated a complex spiritual world or ’Pleroma.’ One element or ’aeon’ in that world, Sophia, fell and produced from her passion and repentance the psychic and material realms of existence. In a movement that typifies the whole soteriological process, Christ came to restore her to her original condition. Humanity is composed of the results of this process, having spiritual, psychic, and material components. The gnoµsis provided by Jesus, a being separate from Christ, awakens the awareness of the spiritual component of humanity about its essential identity with the Godhead and leads to ultimate restoration.

Despite its suppression by ecclesiastical authorities in the third and fourth centuries, Gnosticism continued in the guise of Manichaeism and Mandaeism and in various medieval speculative movements. See also Gospel of Thomas, The; Nag Hammadi; Simon Magus.