To fully understand the NT, which I would think would be something all Christians, not just the Orthodox, would aspire to, the answer quite simply is yes, as Kosta so very completely explained.
In that case God's word, and indeed Christianity itself, is NOT transcendent. It is bound by the Greek. Please correct me if I'm wrong, but when you say "fully", I take that to refer (in part) to key differences in core theology. I disagree. God chose Greek as the original language for the vast majority of the NT fair and square. However, if we believe that Christianity is a revealed faith, then I can't accept that very important truths would lie buried only within the Greek. God already knew all about all the translations that were coming, and it doesn't seem consistent for Him to "hide" the real truth only within one language.
Of course knowledge of and study of the Greek is highly commendable and profitable for the understanding of scripture. Many people of varying Christian faiths have spent years in that pursuit. I just don't think that ALL Protestant translators throughout history were either liars or factually wrong. IOW, I do not think there is a monopoly on understanding Greek for only the followers of Apostolic faiths.
AMEN! The foolishness of the EO to presume God is not in control of His word is really a knee-slapper.
Do the EO believe we should ALL be using ancient Greek texts rather than translations? How do we fulfill the Great Commission then if we're supposed to preach God's word in an archaic language which bears little resemblance to its modern counterpart?
If we begin with the presupposition that God intends to speak through Scripture to His children on earth, then we can be assured God's word will be heard by those to whom He has given ears to hear.
OK