Gnosticism (derived from the Greek word “gnosis; knowledge”) is the well-known phenomenon or movement which dates from the first centuries of church history. The teaching of Gnosticism questioned and/or contradicted the teaching of the church on some of the fundamental truths of Scripture. Apart from Gnosticism, the Early Church also had to deal with the heresy of Arianism. In the Nicene Creed, formulated by the councils of Nicea (325 AD) and Constantinople (381 AD) the universal or catholic church responded officially to the heresies of both Gnosticism and Arianism. In the final edition of the Nicene Creed we also find an article on the unity, holiness, catholicity and apostolicity of the church. Both Gnosticism and Arianism posed a serious threat to the unity of the church. In our times we experience a revival of ancient Gnosticism, both pagan and “Christian”. This revival is also called the New Age or the Age of Aquarius. Within the framework of this new worldview, we are witnessing a rediscovery of gnosis. The discovery and publication of certain ancient gnostic texts like the Nag Hammadi Codices, play a significant role in this revival. Consequently the canon of Scripture is questioned or openly rejected and also the creeds based on that Scripture. The Nicene Creed played a major and decisive role in preserving and maintaining the unity of the church on the basis of the truth of Scripture. This age-old creed is today just as relevant and important in proclaiming and confessing the true faith and preserving the true unity of the church.