For many of us, Gnosticism is difficult to pin down, and this is because it is not itself a religion but a philosophy that piggy-backs on religions. David Grabbe explains how we can see this in Paul's epistles to the Galatians and Colossians, in which he combats Gnosticism's twisting of the truth of Jesus Christ.
Focusing upon Galatians 4:6, John Ritenbaugh reiterates that Jesus Christ constitutes that Spirit that had been designated to dwell within us. There is no third person in a closed trinity. Jesus Christ and God the Father are one in spirit and purpose, purposing to draw us toward that same kind of unity that currently exists between them. The word Elohim is not limited to god-beings, gender, or family. There are two God beings working in such harmony (John 10:30) that they are one family. The Father and the son are both of the God-kind (group, class, family)- creating, ruling beings. Absolute can be considered a synonym for supreme; there is no one to whom God the Father must submit. Jesus Christ did yield to the Father and had as His function revealing the Father. By Jesus' own testimony, Jesus recognized the Father as greater (or superior) than He (John 5:30; 6:38; 8:29; 12:49-50; 14:28). Paul recognized that the Father was superior to Christ in rank (I Corinthians 15:27-28). Revelation 3:12 The lesser is submitting to the greater. As fully spirit, Jesus still recognized the Father's superiority; Jesus was admitting He was not the Absolute God, even though both were equal in terms of their kind. In terms of function and responsibility, God the Father is superior (I Corinthians 8:6, Ephesians 4:4-6, I Timothy 3:17); God's family has hierarchy. Jesus, subject to the Father- the Absolute God, is our Lord, Master, and Savior, and High Priest, and entirely worthy of our worship (Matthew 9:18, John 9:38).Jesus, His cousin John the Baptist, and the Apostle Paul gave substantiation to Christ's eternal pre- existence (John 1:1-2,30, 3:13, 8:58, 1 Corinthians 10:9, Hebrews 11:27)The God of the Old Testament was Jesus Christ. Jesus begotten siblings, once born into the God family as God-beings, are worthy of worship (Revelation 3:9); they are NOT the God head.
Since God has authorized no day other than the Sabbath, John Ritenbaugh observes that Sunday worship is a pagan deviation, perpetuated by Hellenistic Gnosticism, a multi-faceted movement that despises Yahweh, the Sabbath, and God's laws. Though Constantine enforced Sunday-keeping (the counterfeit Sabbath) on Western culture, the ugly tentacles of Gnosticism had already surfaced in Paul's warning to the Colossians about "rudiments of the world," angel worship (actually demon worship), and "white" magic. Gnostics have incorporated Neo-Platonic notions of real (supposedly appearing in the Pleroma) and corporeal (corrupt, earthly, physical forms) to counterfeit the shadow and reality concept as described by Paul. Christ, not angels, is the reality and the fullness of God. Antinomianism, Dispensationalism, eternal security, and irresistible grace—all assimilated into evangelical Protestantism—have all derived from Hellenistic Gnosticism.
Galatians 4:9-10 is a favorite target of those who claim Christians no longer need to observe God's holy days. Is that really what Paul said? Earl Henn shows that he meant something entirely different!
John Ritenbaugh affirms that the way to be undefiled (to become sanctified, developing character) is to walk in the Law of the Lord (Psalm 119:1). We must do God's Word or it will never be a part of us. The Colossian Christians (Colossians 2:16-17) were criticized by Gnostic infiltrators for the way they were keeping the holy days. Paul admonishes the embattled Colossians not to let any man judge them for the way they were keeping the holy days. Contrary to some misguided Bible scholars, (1) keeping the Sabbath is not a doctrine of men; (2) what Paul condemns is a philosophy; God's word is not a philosophy. (Paul is concerned about the context in the way this philosophy was impacting on those keeping God's Word.) (3) Paul calls this Gnostic system (not God's holy days) empty, vain deceit, and (4) he names the authors of this Gnostic system and its recipients demons.