I was searching google for “primacy of the four gospels” to see what I could find. And I chanced upon the following from here:

Section 4, “The Study of the Gospels is the First Fruits Offered by These Priests of Christianity.” The primacy of the four Gospels as the “first fruits of the Scriptures.” Origen clarifies that in one sense the epistles of the NT are not properly called “Scripture,” since when Paul says things like, “I say, and not the Lord” and “so I ordain in all the churches,” etc. Also when Paul says “Every Scripture is inspired and profitable by God” he is probably not referring to his own writings. The four Gospels are the first fruits of the Scriptures for Origen in that they are the first which are offered to God, after the whole has become ripe.

I wish I knew what writing of Origen was being referred to.  But, even if I did, its probably one that still languishes in Greek or Latin.  Since both Catholics and Protestants consider Origen to have been heretical on certain points, a lot of his writings haven’t been translated into English.  If anyone is familiar with where Origen says that the epistles are not properly Scripture, please shoot me a line.

Ok, I found it actually.  That site did say it was from Origen’s commentary on John. I just missed that.  So here it is, from Origin’s Commentary on John, Book I, Chapter 4:

Now our whole activity is devoted to God, and our whole life, since we are bent on progress in divine things. If, then, it be our desire to have the whole of those first fruits spoken of above which are made up of the many first fruits, if we are not mistaken in this view, in what must our first fruits consist, after the bodily separation we have undergone from each other, but in the study of the Gospel? For we may venture to say that the Gospel is the first fruits of all the Scriptures. Where, then, could be the first fruits of our activity, since the time when we came to Alexandria, but in the first fruits of the Scriptures? It must not be forgotten, however, that the first fruits are not the same as the first growth. For the first fruits are offered after all the fruits (are ripe), but the first growth before them all. Now of the Scriptures which are current and are believed to be divine in all the churches, one would not be wrong in saying that the first growth is the law of Moses, but the first fruits the Gospel. For it was after all the fruits of the prophets who prophesied till the Lord Jesus, that the perfect word shot forth.

And then chapter 5 of the same:

Here, however, some one may object, appealing to the notion just put forward of the unfolding of the first fruits last, and may say that the Acts and the letters of the Apostles came after the Gospels, and that this destroys our argument to the effect that the Gospel is the first fruits of all Scripture. To this we must reply that it is the conviction of men who are wise in Christ, who have profited by those epistles which are current, and who see them to be vouched for by the testimonies deposited in the law and the prophets, that the apostolic writings are to be pronounced wise and worthy of belief, and that they have great authority, but that they are not on the same level with that “Thus says the Lord Almighty.”  Consider on this point the language of St. Paul. When he declares that 2 Timothy 3:16 “Every Scripture is inspired of God and profitable,” does he include his own writings? Or does he not include his dictum, 1 Corinthians 7:12 “I say, and not the Lord,” and 1 Corinthians 7:17 “So I ordain in all the churches,” and 2 Timothy 3:11 “What things I suffered at Antioch, at Iconium, at Lystra,” and similar things which he writes in virtue of his own authority, and which do not quite possess the character of words flowing from divine inspiration. Must we also show that the old Scripture is not Gospel, since it does not point out the Coming One, but only foretells Him and heralds His coming at a future time; but that all the new Scripture is the Gospel. It not only says as in the beginning of the Gospel, John 1:29 “Behold the Lamb of God, which takes away the sin of the world;” it also contains many praises of Him, and many of His teachings, on whose account the Gospel is a Gospel. Again, if God set in the Church Ephesians 4:11 apostles and prophets and evangelists (gospellers), pastors and teachers, we must first enquire what was the office of the evangelist, and mark that it is not only to narrate how the Saviour cured a man who was blind from his birth, John 9:1 or raised up a dead man who was already stinking, John 11:39 or to state what extraordinary works he wrought; and the office of the evangelist being thus defined, we shall not hesitate to find Gospel in such discourse also as is not narrative but hortatory and intended to strengthen belief in the mission of Jesus; and thus we shall arrive at the position that whatever was written by the Apostles is Gospel. As to this second definition, it might be objected that the Epistles are not entitled “Gospel,” and that we are wrong in applying the name of Gospel to the whole of the New Testament. But to this we answer that it happens not unfrequently in Scripture when two or more persons or things are named by the same name, the name attaches itself most significantly to one of those things or persons. Thus the Saviour says, Matthew 23:8-9 “Call no man Master upon the earth;” while the Apostle says that Masters have been appointed in the Church. These latter accordingly will not be Masters in the strict sense of the dictum of the Gospel. In the same way the Gospel in the Epistles will not extend to every word of them, when it is compared with the narrative of Jesus’ actions and sufferings and discourses. No: the Gospel is the first fruits of all Scripture, and to these first fruits of the Scriptures we devote the first fruits of all those actions of ours which we trust to see turn out as we desire.