If someone asked a Roman Catholic who is the ultimate authority in the church, in other words, who guarantees that the doctrines of the church are true, the answer would be the Pope, usually together with the bishops, but occasionally alone is infallible.
If one asked a Protestant, the answer would be that the Bible alone is the ultimate authority, interpreted as best as one can. How would we as Orthodox answer this question? Some would say that the bishops, meeting in council, are “infallible.” Today we are commemorating the Fathers of the first six ecumenical councils, and we certainly believe that what they taught is true and the authoritative source of Orthodox belief.
However, we should not say that councils are ipso facto infallible because there have been councils of bishops which thought they were ecumenical councils but who actually taught heresy.
So what is the ultimate source of truth for us as Orthodox? We would say that it is the teaching of the councils which have been “received” by the church. Now this does not mean that after the bishops define some truth at a council everybody else gets to vote, as in a one person, one vote system. Rather, the writing of the theologians, (monastics, clerical or lay), the use of the council’s decisions in the liturgy of the church and in icons, the veneration of the council fathers as saints and so on show that council’s teaching have been received by the church. Now this is a ‘messy’ process, compared to the “infallible” teaching of the Pope or the inerrancy of the Bible. But it is in this way that the teachings of the councils have been accepted by the church. Jesus Christ promised to send the Holy Spirit to the church after he, Jesus, ascended into heaven and it is the presence of the Holy Spirit in the church guiding the church into all truth. If we want to use the word infallible we say that the whole church, the people of God, is infallible.
Troparion — Tone 8
You are most glorious, O Christ our God! You have established the Holy Fathers as lights on the earth! Through them you have guided us to the true faith! O greatly Compassionate One, glory to You!
Kontakion — Tone 8
The Apostles’ preaching and the Fathers’ doctrines have established one faith for the Church. Adorned with the robe of truth, woven from heavenly theology, It defines and glorifies the great mystery of Orthodoxy!