This is following the accepted and established doctrines of the church as based on the creeds of the early church.  However, over time various doctrines, false teachings, traditions, philosophies and viewpoints which cannot be considered orthodox have subtly crept into much of Christianity. If these hold more authority than the Bible or contravene

Before accepting any teaching clarify it is scriptural

its standards they must be rejected (Act 17:11; Col 2:8,20-23; 2 Tim 3:14-17). We are instructed to watch our lifestyle and doctrine closely, for in today’s world there are so many false teachings and New Age thought patterns that seek to captivate people’s minds turning them aside from the truth of Christ as contained in the Bible (Isa 53:6a; Eph 4:14; 1 Tim 4:16; Heb 13:9; 2 Pet 2:15).

The Eastern Orthodox Church is a grouping of 13 self-governing churches called by the nation in which they are located (eg. The Russian Orthodox Church is in Russia). They hold similar views on doctrine, the sacraments (baptism, communion) and liturgy (prescribed words and set forms) with each country administering their own affairs under their own ruling figure. Like Catholics and Protestants, they affirm the Trinity, the Bible as the Word of God, Jesus as God the Son and many other biblical doctrines to varying degrees, but overall have more in common with Catholics than Protestant Christians. Their traditions and the Bible are considered equal authorities, and consequently several of their doctrines are faulty, such as praying for the dead, the baptism of infants without any reference to individual responsibility and faith, and the possibility of receiving salvation after death. Justification by faith is virtually absent from their teachings. Although there are genuine Christians in the Orthodox Church, the organisation as a whole is not adhering faithfully to the truth of the Bible. 

See also: creeds, doctrine, false teaching, sect, theology, tradition, truth.