The Orthodox Church throughout the ages has maintained a continuity of faith and love with the apostolic community which was founded by Christ and sustained by the Holy Spirit. Orthodoxy believes that she has preserved and taught the historic Christian Faith, free from error and distortion, from the time of the Apostles. She also believes that there is nothing in the body of her teachings which is contrary to truth or which inhibits real union with God. The air of antiquity and timelessness which often characterizes Eastern Christianity is an expression of her desire to remain loyal to the authentic Christian Faith.
Orthodoxy believes that the Christian Faith and the Church are inseparable. It is impossible to know Christ, to share in the life of the Holy Trinity, or to be considered a Christian, apart from the Church. It is in the Church that the Christian Faith is proclaimed and maintained. It is through the Church that an individual is nurtured in the Faith.
God is the source of faith in the Orthodox Church. Orthodoxy believes that God has revealed Himself to us, most especially in the revelation of Jesus Christ, whom we know as the Son of God. This Revelation of God, His love, and His purpose, is constantly made manifest and contemporary in the life of the Church by the power of the Holy Spirit.
The doctrine affirms that there is only One God, in whom there are three distinct Persons. In other words, when we encounter the Father, the Son, or the Holy Spirit, we are truly experiencing contact with God. While the Holy Trinity is a mystery which can never be fully comprehended, Orthodoxy believes that we can truly participate in the Trinity through the life of the Church, especially through our celebration of the Eucharist and the Sacraments, as well as the non-sacramental services.
Together with the belief in the Holy Trinity, the doctrine of the Incarnation occupies a central position in the teaching of the Orthodox Church. According to Orthodox Faith, Jesus is much more than a pious man or a profound teacher of morality. He is the “Son of God who became the Son of Man.” The Church believes that, as the unique God-man, Jesus Christ has restored humanity to fellowship with God.
Excerpt taken from Rev. Thomas Fitzgerald article, Greek Orthodox Archdiocese of America website. To read more follow this link.