Mark, the follower of Peter, while Peter publicly preached the Gospel at Rome before some of Cæsar’s equites, and adduced many testimonies to Christ, in order that thereby they might be able to commit to memory what was spoken, of what was spoken by Peter, wrote entirely what is called the Gospel according to Mark. As Luke also may be recognised by the style, both to have composed the Acts of the Apostles, and to have translated Paul’s Epistle to the Hebrews.
— Clement of Alexandria, Commentary on 1 Peter, fragments from the Latin translation of M. Aurelius Cassiodorus,
And in the Hypotyposes, in a word, he has made abbreviated narratives of the whole testamentary Scripture; and has not passed over the disputed books,—I mean Jude and the rest of the Catholic Epistles and Barnabas, and what is called the Revelation of Peter. And he says that the Epistle to the Hebrews is Paul’s, and was written to the Hebrews in the Hebrew language; but that Luke, having carefully translated it, gave it to the Greeks, and hence the same colouring in the expression is discoverable in this Epistle and the Acts; and that the name “Paul an Apostle” was very properly not prefixed, for, he says, that writing to the Hebrews, who were prejudiced against him and suspected, he with great wisdom did not repel them in the beginning by putting down his name.
Again, in the same books Clement has set down a tradition which he had received from the elders before him, in regard to the order of the Gospels, to the following effect. He says that the Gospels containing the genealogies were written first, and that the Gospel according to Mark was composed in the following circumstances: Peter having preached the word publicly at Rome, and by the Spirit proclaimed the Gospel, those who were present, who were numerous, entreated Mark, inasmuch as he had attended him from an early period, and remembered what had been said, to write down what had been spoken. On his composing the Gospel, he handed it to those who had made the request to him; which coming to Peter’s knowledge, he neither hindered nor encouraged. But John, the last of all, seeing that what was corporeal was set forth in the Gospels, on the entreaty of his intimate friends, and inspired by the Spirit, composed a spiritual Gospel.
— EUSEBIUS: ECCLESIASTICAL HISTORY, VI. 14.
Jude, who wrote the Catholic Epistle, the brother of the sons of Joseph, and very religious, whilst knowing the near relationship of the Lord, yet did not say that he himself was His brother. But what said he? “Jude, a servant of Jesus Christ,”—of Him as Lord; but “the brother of James.” For this is true; he was His brother, (the son) of Joseph.
— Clement of Alexandria, Commentary on Jude, fragments from the Latin translation of M. Aurelius Cassiodorus,
We have learned from none others the plan of our salvation, than from those through whom the Gospel has come down to us, which they did at one time proclaim in public, and, at a later period, by the will of God, handed down to us in the Scriptures, to be the ground and pillar of our faith. … Matthew also issued a written Gospel among the Hebrews in their own dialect, while Peter and Paul were preaching at Rome, and laying the foundations of the Church. After their departure, Mark, the disciple and interpreter of Peter, did also hand down to us in writing what had been preached by Peter. Luke also, the companion of Paul, recorded in a book the Gospel preached by him. Afterwards, John, the disciple of the Lord, who also had leaned upon His breast, did himself publish a Gospel during his residence at Ephesus in Asia.
–Irenaeus. Against Heresies. III.I.
Such, then, being the state of the case, and this number being found in all the most approved and ancient copies [of the Apocalypse], and those men who saw John face to face bearing their testimony [to it]; while reason also leads us to conclude that the number of the name of the beast, [if reckoned] according to the Greek mode of calculation by the [value of] the letters contained in it, will amount to six hundred and sixty and six; that is, the number of tens shall be equal to that of the hundreds, and the number of hundreds equal to that of the units (for that number which [expresses] the digit six being adhered to throughout, indicates the recapitulations of that apostasy, taken in its full extent, which occurred at the beginning, during the intermediate periods, and which shall take place at the end),—I do not know how it is that some have erred following the ordinary mode of speech, and have vitiated the middle number in the name, deducting the amount of fifty from it, so that instead of six decads they will have it that there is but one.
–Irenaeus. Against Heresies. V.XXX.