In the last three or four years Michael Kruger of Reformed Theological Seminary, Luke Wayne, a writer-researcher for CARM (Christian Apologetics & Research Ministry), Matthew Ervin of Tyndale Theological Seminary and others have called attention to a reference to the entire canon of the New Testament in a homily (sermon) on Joshua by the early Christian theologian Origen. Origen died circa AD 254, and the sermon is usually dated a few years before that (circa 250). Below is the Latin text from Patrologiae Cursus Completus, Volume 12, Origen (pp. 857-858), followed by two English translations.
(Homily on Joshua, No. 7)
Veniens vero Dominus noster Jesus Christus, cujus ille prior filius Nave designabat adventum, mittit sacerdotes apostolos suos portantes tubas ductiles, prædicationis magnificam cœlestemque doctrinam. Sacerdotali tuba primus in Evangelio suo Matthæus increpuit. Marcus quoque, Lucas et Joannes suis singulis tubis sacerdotalibus cecinerunt. Petrus etiam duabus Epistolarom suarum personat tubis. Jacobus quoque el Judas. Addit nihilominus adhuc et Joannes tuba canere per Epistolas suas et Apocalypsim,[i] et Lucas apostolorum gesta describens. Novissime autem ille veniens, qui dixit : puto autem nos Deus novissimos apostolos ostendit, et in quatuordecim epistolarum suarun fulminans tubis, muros Jericho, et omnes idololatriæ machinas, et philosophorum dogmata usque ad fundamenta dejecit.[ii]
But when our Lord Jesus Christ comes, whose arrival that prior son of Nun designated, he sends priests, his apostles, bearing “trumpets hammered thin,” the magnificent and heavenly instruction of proclamation. Matthew first sounded the priestly trumpet in his Gospel; Mark also; Luke and John each played their own priestly trumpets. Even Peter cries out with trumpets in two of his epistles; also James and Jude. In addition, John also sounds the trumpet through his epistles and Revelation, and Luke, as he describes the Acts of the Apostles. And now that last one comes, the one who said, “I think God displays us apostles last,” and in fourteen of his epistles, thundering with trumpets, he casts down the walls of Jericho and all the devices of idolatry and dogmas of philosophers, all the way to the foundations.[iii]
So too our Lord, whose advent was typified by the son of Nun, when he came sent his apostles as priests bearing well-wrought trumpets. Matthew first sounded the priestly trumpet in his Gospel. Mark also, Luke and John, each gave forth a strain on their priestly trumpets. Peter moreover sounds loudly on the twofold trumpet of his epistles; and so also James and Jude. Still the number is incomplete, and John gives forth the trumpet-sound in his epistles and Apocalypse; and Luke while describing the acts of the apostles. Lastly however came he who said, I think that God hath set forth us Apostles last of all, [1 Cor. 4:9] and thundering on the fourteen trumpets of his epistles threw down even to the ground the walls of Jericho, that is to say all the instruments of idolatry and the doctrines of philosophers.
In addition to this sermon, Origen names the eight authors of these 27 New Testament books in his allegorical Homily No. XIII from Genesis on the wells that Isaac dug.[iv]
Isaac, therefore, digs also new wells, nay rather Isaac’s servants dig them. Isaac’s servants are Matthew, Mark, Luke, John; his servants are Peter, James, Jude; the apostle Paul is his servant. These all dig the wells of the New Testament.
[i] The words et Apocalypsim are missing from some manuscripts of this homily. The words “his epistles” [of John] are sufficient to cover the three general epistles and the epistle to the seven churches of Asia, even if the words et Apocalypsim are not original and merely added as explanatory.
[ii] See also On the Canon of the Scriptures of the Old and New Testament, and on the Apocrypha by Christopher Wordsworth (London: Francis & John Rivington, 1848, in Appendix A)