When we say the creed each Sunday, we proclaim the faith into which we were baptized. Although we are not entirely certain where creeds come from, we know that catechumens in the early Church had to learn answers to a series of questions about the core beliefs of the Church. They repeated these publicly as part of their baptismal ceremony to attest to their belief. Creeds may have originated in part as a condensed version of these answers, and would have varied locally (one of the most famous surviving examples is known to us as The Apostles’ Creed – it was actually the local creed used in Rome). The Council of Nicaea produced a Creed in 325 and later in the same century the Council of Constantinople (381) produced another which it said expressed the faith of Nicaea, and it is this we use today. Bishops had to sign up to this creed when they were ordained, and gradually, over many decades it came to be used in the liturgy and in catechesis.
Catechumens professing the faith at their baptism did need to have a basic grasp of the creed, but not perhaps for the reason you might think. Gregory of Nyssa, a bishop who was present at the council of Constantinople, worried that a false conception of the Trinity would undermine the Christian at the very beginning of his or her new life in Christ. Why? Not because we have to understand in order to for God to save us, but because we do develop ideas about God in our imaginations. The ideas in the creed help us to develop our faith, hope, and love. Doctrine is not a barrier to keep out those who have difficulty comprehending it (such as children, for example, whom Jesus said we ought to be like), but a gift to keep our imaginations faithful.
Part of a series on the Creed by Medi Ann Volpe