Origen's Commentary on the Gospel of John: The Old Testament, Typified by John, is the Beginning of the Gospel

In addition to what we have said, there is also this to be considered about the Gospel, that in the first instance it is that of Christ Jesus, the head of the whole body of the saved; as Mark says, “The beginning of the Gospel of Jesus Christ.” Then also it is the Gospel of the Apostles; whence Paul says, “According to my Gospel.” But the beginning of the Gospel—for in respect of its extent it has a beginning, a continuation, a middle, and an end—is nothing but the whole Old Testament. John is, in this respect, a type of the Old Testament, or, if we regard the connection of the New Testament with the Old, John represents the termination of the Old. For the same Mark says: “The beginning of the Gospel of Jesus Christ, as it is written in Isaiah the prophet, Behold I send my messenger before thy face, who shall prepare thy way. The voice of one crying in the wilderness, Prepare ye the way of the Lord, make His paths straight.” And here I must wonder how the dissentients can connect the two Testaments with two different Gods. These words, were there no others, are enough to convict them of their error. For how can John be the beginning of the Gospel if they suppose he belongs to a different God, if he belongs to the demiurge, and, as they hold, is not acquainted with the new deity? And the angels are not entrusted with but one evangelical ministry, and that a short one, not only with that addressed to the shepherds. For at the end an exalted and flying angel, having the Gospel, will preach it to every nation, for the good Father has not entirely deserted those who have fallen away from Him. John, son of Zebedee, says in his Apocalypse: “And I saw an angel flying in the midst of heaven, having the Eternal Gospel, to preach it to those who dwell upon the earth, and to every nation, and tribe, and tongue, and people, saying, with a loud voice, Fear God and give Him glory, for the hour of His judgment hath come, and worship Him that made the heaven, and the earth, and the sea, and the fountains of waters.”