I respond to this ping with trepidation, because I have no desire to get into a major discussion, especially on a topic that has been hashed out extensively already --granted, that describes this entire thread. :-)
That said, I will pick up on something that both qua and Kosta have alluded to in different ways. Kosta (jokingly, I hope) referred to himself as a "heretic" for not believing certain things. Qua alludes to his perception that Kosta's portrayal of OT - NT (dis)continuity is perhaps not the consensus view of Orthodoxy.
It certainly is not, although that does not at all make Kosta a heretic! :-)
The Gospels, Acts, and the Epistles all contain ample evidence that Christ and the Apostles portrayed the Christian faith as being in direct continuity with the faith of Adam, Abel, Enoch, Noah, Abraham, Isaac, Jacob, Moses, David, and all the prophets. The fact that Christ "came unto his own, and his own received him not" does not change this self-understanding.
The writings of the fathers, early or later, continue this self-understanding of the Church as the New Israel and as the genuine continuity with the faith of the patriarchs and prophets. Christ overturned, according to this view, the perverted Judaism of his day, but stood in continuity with the faith that he himself, as the "He Who Is", instilled into the Hebrew people through revealing Himself to the patriarchs and prophets.
St. Athanasius stood "contra mundum" while the whole world was Arian, yet he was the one who was right. So also the fact that a majority of Jews (certainly the vast majority of the leadership of that particular time) did not know their own Scriptures and recognize and accept Christ and the teachings of the Apostles does not change the fact that the Christian Church was and is the continuity of the faith of the patriarchs and prophets.
According to this understanding, post-Christian Judaism (or the Judaism of the Pharisees, Sadducees, and scribes who were contemporaries of Christ) is not the place to look if one wants to understand the pre-Christian faith of the Hebrew patriarchs and prophets.
Again, I have painted with broad brush-strokes, but this is the traditional self-understanding of Christianity as I understand it from the New Testament and the writings of the Fathers. One can agree or disagree with this self-understanding, and I am unaware of anything that would indicate that disagreeing would make someone a heretic, but it is impossible (to me) to deny that this is the traditional consensus self-understanding within which all of the Scriptures are interpreted in the Orthodox Church.
I would also add that Kosta is precisely correct in stating to qua that the faith articulated at Chalcedon and the other ecumenical councils was there from the very beginning. Where qua is missing the boat is his seeming insistence that a faith unarticulated in specific terminology must be a faith that doesn't exist -- i.e. that a belief articulated with precision for the first time is a belief that has only newly sprung into being.
Most self-evidently, qua does not apply this standard to his own faith, since the specific formulations of the Reformation are no-where to be found in those exactly exposited forms anywhere in the Scripture -- yet he clearly believes that those formulations are exactly the same faith taught by the Apostles.
When I am asked "where is ______ in the Bible?", I like to answer that it is in the opening words of the Acts of the Apostles: "...until the day in which he was taken up, after that he through the Holy Ghost had given commandments unto the apostles whom he had chosen. To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God."
Everything has followed that: the recording of the events in the life of Christ and the recording of many of his words in the Gospels; the recording of the action of the Holy Spirit through the Apostles in the early Church in the Acts; the exposition in the Epistles of what Christ taught the apostles...
From the very beginning, everything was understood and interpreted in the light of this knowledge of Christ -- this is why when a replacement was being chosen for Judas Iscariot, the Apostles insisted that this person had to have been one "of these men which have companied with us all the time that the Lord Jesus went in and out among us, beginning from the baptism of John, unto that same day that he was taken up from us..."
Very useful post, Agrarian.
Let me underscore one point, perhaps a bit self-servingly as a Catholic. It is a very common misunderstanding of the Church that she creates dogmata through her councils. While the Catholic Church is rather strident in formulating doctrine whenever a need for one is felt, and does so even in absence of the Orthodox sister Church, the self-understanding of the Church is that it is not a new teaching but an elaboraton of the faith of the fathers. Doctrines are promulgated when they are challenged (most recently, by the Reformers) or when an extraneous development requires pastoral intervention (as with various technoliogical innovations).
I don't profess my dubts and my ingorance as truth so I guess that makes me one -- a little bit. :)
I don't think that the Jews who rejected Jesus believed that He was starting a new religion. They did not reject His beliefs; they rejected and still reject the notion that a meshiach is God. To them that's like the LDS saying that Jesus' brother is Satan, or that Blessed Theotokos conceived by the "Holy Spirit overshadowing her" (implying it was a carnal union), as understood in biblical terms elsewhere.
Without His divnity Christianity would to this day remain a Jewish sect.