In the 4th Century, the Church composed a uniform, official creed for the whole Church as written by the First and Second Ecumenical (meaning worldwide) Councils. It's a statement of faith written by the entire Christian Church under the guidance of the Holy Spirit.

The Nicene Creed is recognized as the symbol of faith and is the basis of Christian education. It is recited at time of baptism by the sponsor, and by those who are admitted to the fellowship of the faith. It is an affirmation of what each member of the church believes. It's also recited in every liturgy as a constant renewal of our baptismal confession of faith.

The "filioque" clause

The Nicene Creed states that the Holy Spirit "proceed from the Father." The Western Church later inserted the words "and from the Son," meaning that the Holy Spirit proceeds from the Father and the Son. This is the "filioque" clause which caused difference between the Western and Eastern Churches. However, the Orthodox Church preserved the Nicene Creed in its originality. First, because the Ecumenical Council forbade changes unless by another Ecumenical Council since it belonged to the whole Church, and not one small part of the Church should alter it. Additionally, the Orthodox believe it to be untrue and are taught what the Bible teaches, which is Christ sends the Spirit; that the Spirit proceeds from the Father as the source of the Trinity.

Thus, the Orthodox Church has preserved the Nicene Creed is its original form.