I love the Nicene Creed! I was not raised in a church tradition that emphasized creeds, In fact we avoided them. We were taught that we were about the authority of Scripture only and creeds undermined the Scriptures and added to them. Over the years, however, as I have read theology and reflected theologically, I have come to appreciate the Christian creedal tradition and see it's indispensable benefit to the church that seeks to be faithful to the Gospel.
So why are creeds important?
First, creeds are important because they remind us that there are non-negotiables when it comes to Christian doctrine. As an individual I cannot make Christianity whatever I wish it to be. I do not make up the faith; I receive it. Of course, I bring myself, my personal narratives, and my context to my faith, but there are certain affirmations that must be made for the faith to be Christian faith. Many years ago, the great neo-orthodox theologian, Emil Brunner wrote a basic primer on Christianity entitling it, Our Faith. Brunner knew that Christian faith would be distorted if each individual only assumed that her or his faith belonged exclusively and only to her or him. Without the faith of those who have gone before, the faith of an exclusively personal faith is not worth having. We cannot see over the horizon to glimpse the Kingdom of God without standing on the shoulders of our faithful mothers and fathers who have passed the identity they have received to us. Doctrine does matter. I have not been given the right or authority to reject the essentials of Christianity because they go against my modern sensibilities.
Second, creeds remind us that while there are non-negotiables, there is also plenty of room for diversity and difference of opinion. It must not be forgotten that the Creeds are brief. There is much they do not mention. The temptation for Christians throughout history is to major in the minors, or to, as in the words of Father John Wesley, place at the center those things that "do not strike at the root" of the faith. For some Christians inerrancy is an important doctrine, but never has the church affirmed or denied that in a creed. Historically, in the debates over the atonement, some have preferred one understanding of Christ's work over another, and some have even rejected one or more aspects of atonement in favor of only one. But never has the ecumenical church taken a position on which aspect of the atonement is the only correct one. In their wisdom they understood that no one "theory" of Christ's work adequately explains what it means for Christ to be our Savior. What Jesus has done for us is too rich and too wonderful to be reduced only to sacrificial substitution or exemplary love to the exclusion of everything else.
Third, and finally, the Creeds do not undermine Scripture, nor do they add to the Bible in a way that rejects Scripture. The creeds are the necessary result of a discussion that the church would have to have because of the testimony of the New Testament, particularly of the witness it bears to Jesus Christ-- who he is and what he has done. The Nicean theologians knew that what was finally affirmed about the person of Jesus made a difference for what his work accomplished. At the Council of Nicaea, the central question swirling in the background was, "If we say "thus and so" about Jesus, what does it mean for our salvation?" They understood all too well that the answer to that question mattered.
I could add further reasons, but I do not want to lose the trinitarian character of this post-- That too matters; for our creeds rightly affirm on account of the New Testament witness, that the Trinity is the essential Christian doctrine of God.
So, as one who grew up knowing that creeds existed, but having no idea what they were, nor having ever recited one, I now utter those words in worship with great conviction, thankful to God that I have received and accepted these words as my faith, precisely because they are first and foremost, our faith.