In this first message to mankind, Satan sows seeds of doubt as to whether God can be trusted. Satan's very first words were, "Has God indeed said. . . ?" Spoken or not, this sentiment that God is untrustworthy, and that His Word is suspect, has been a regular feature in mankind's relationship with God ever since.
The Gnostics were no exception—in fact, they are a prime example. In its most basic sense, Gnosticism is knowing, but its knowledge, while sometimes including the Word of God, does not have it as its foundation. Instead, more than what was contained in Scripture, Gnostics valued what they experienced, what elders told them, or what they learned from "angels," astrology, or chemistry (alchemy). Thus, we see elements of Gnosticism in Galatians: a mixture of "lucky days," to which they ascribed spiritual significance (part of their worship prior to conversion) and a belief, brought in by Judaizers or perhaps even an "angel" (Galatians 1:8), that justification could come by works of the law.
Judaism, though it has its roots in the Old Testament, sees God's Word through the lens of Hellenism (Greek thought) and the traditions of Jewish scholars and teachers through the centuries. The Galatian Christians gave God's Word lip service, but did not depend on it as the source of their beliefs and practices. If they had, they would not have returned to pagan "days, months, seasons, and years," nor believed that justification could ever result from good works—a concept that is read into the Old Testament, but not actually found there.
Similarly, the Colossian Christians were affected by an ascetic form of Gnosticism that included "ordinances" (KJV) or "regulations" (NKJV) that are not found in God's Word but were the commandments and doctrines of men (Colossians 2:20-23), as well as demons, the "basic principles of the world" (Colossians 2:8).
This same distrust of God's Word is readily seen in today's Catholicism and Protestantism. The Catholic Church holds that Scripture is only one of three sources from which its dogma is derived—the other two being divine revelation and the writings and traditions of previous Catholic saints. The Bible, while generally utilized as the source of doctrine, can be easily overridden by the words of a Pope or other theologian, living or dead. Once again, human words and traditions are considered more trustworthy than God's.
In some respects, Protestantism has a higher regard for Scripture. However, it, too, accepts the traditions of men in such beliefs as the Trinity, the immortality of the soul, going to heaven, observing Christmas and Easter, and venerating the first day of the week (which the Catholic Church rightly points out makes sense only if one accepts Rome's authority, for there is no scriptural authority for keeping any day holy but the Sabbaths).
Modern Gnostics who believe in "progressive revelation" have also succumbed to this first of Satan's ploys. While God does reveal things to us, the critical point is that what is revealed—if it truly comes from Him—will never contradict what He has already revealed in His Word. "God is not a man, that He should lie" (Numbers 23:19). Yet progressive revelation advocates believe that their revelations are more authoritative than the Bible, rather than complementing and harmonizing with it, making them ripe for satanic influence under the guise of God revealing something new to them. They may sincerely believe that God speaks to them, yet they simultaneously mistrust what He has already said in inspired Scripture. They tend to shy away from Bible study, concluding that they do not need it since God speaks directly to them, and if there is anything important, God will let them know.
Romans 10:17 tells us that "faith comes by hearing, and hearing by the word of God." But Satan knows this too and believes that, if he can undermine the trustworthiness of God and the validity of His Word, he can destroy the faith necessary for salvation. Currently, the Bible's legitimacy is undergoing an intense assault. Due to popular Gnostic writings like the Gospel of Judas and the Gospel of Thomas, as well as The Da Vinci Code book and movie, many people are questioning why we have the Bible that we do and wondering if something in the ancient apocryphal writings, if it were known, would change Christianity as we know it. Rather than quibbling about this or that point of doctrine, Satan seems to be gunning for the whole package by asserting that the Word of God is subject to the whims of men and thus cannot be trusted. At every turn, faith founded in God's Word is being undermined.
David C. Grabbe
Whatever Happened to Gnosticism? Part Three: Satan's Three Heresies