Question: "What is the Eastern Orthodox Church and what are the beliefs of Orthodox Christians?"
Answer: The Eastern Orthodox Church is not a single church but rather a family of 13 self-governing bodies, denominated by the nation in which they are located (e.g., the Greek Orthodox Church, Russian Orthodox Church). They are united in their understanding of the sacraments, doctrine, liturgy, and church government, but each administers its own affairs.
The head of each Orthodox church is called a "patriarch" or "metropolitan." The patriarch of Constantinople (Istanbul, Turkey) is considered the ecumenical - or universal - patriarch. He is the closest thing to a counterpart to the Pope in the Roman Catholic Church. Unlike the Pope, who is known as VICARIUS FILIUS DEI (the vicar of the Son of God), the bishop of Constantinople is known as PRIMUS INTER PARES (the first amongst equals). He enjoys special honor, but he has no power to interfere with the 12 other Orthodox communions.
The Orthodox Church claims to be the one true church of Christ, and seeks to trace its origin back to the original apostles through an unbroken chain of apostolic succession. Orthodox thinkers debate the spiritual status of Roman Catholics and Protestants, and a few still consider them heretics. Like Catholics and Protestants, however, Orthodox believers affirm the Trinity, the Bible as the Word of God, Jesus as God the Son, and many other biblical doctrines. However, in doctrine, they have much more in common with Roman Catholics than they do with Protestant Christians.
Sadly, the doctrine of justification by faith is virtually absent from the history and theology of the Orthodox Church. Rather, Orthodoxy emphasizes theosis (literally, "divinization"), the gradual process by which Christians become more and more like Christ. What many in the Orthodox tradition fail to understand is that "divinization" is the progressive result of salvation, not a requirement for salvation itself. Other Orthodox distinctives that are in conflict with the Bible include:
The equal authority of church tradition and Scripture
Discouragement of individuals interpreting the Bible apart from tradition
The perpetual virginity of Mary
Prayer for the dead
Baptism of infants without reference to individual responsibility and faith
The possibility of receiving salvation after death
The possibility of losing salvation
While the Eastern Orthodox Church has claimed some of the church's great voices, and while there are many of the Orthodox traditions that have a genuine salvation relationship with Jesus Christ, the Orthodox church itself does not speak with a clear message that can be harmonized with the biblical gospel of Christ. The call of the Reformers for "Scripture alone, faith alone, grace alone, and Christ alone" is missing in the Eastern Orthodox Church, and that is too precious a treasure to do without.