1 Timothy 6:13. "Who witnessed before Pontius Pilate." For He testified by what he did that He was Christ the Son of God.
2 Timothy 2:2. "By many witnesses; " that is, the law and the prophets. For these the apostle made witnesses of his own preaching.
Eusebius: Ecclesiastical History, Book. VII. II. 1.
To James the Just, and John and Peter, the Lord after His resurrection imparted knowledge ( th/n gnw=sin .) These imparted it to the rest of the apostles, and the rest of the apostles to the Seventy, of whom Barnabas was one.
Eusebius: the Same, II. 2.
And of this James, Clement also relates an anecdote worthy of remembrance in the seventh book of the Hypotyposes, from a tradition of his predecessors. He says that the man who brought him to trial, on seeing him bear his testimony, was moved, and confessed that he was a Christian himself. Accordingly, he says, they were both led away together, and on the way the other asked James to forgive him. And he, considering a little, said, "Peace be to thee" and kissed him. And so both were beheaded together.
Eusebius: the Same, VI. 14.
And now, as the blessed Presbyter used to say, since the Lord, as the Apostle of the Almighty, was sent to the Hebrews, Paul, as having been sent to the Gentiles, did not subscribe himself apostle of the Hebrews, out of modesty and reverence for the Lord, and because, being the herald and apostle of the Gentiles, his writing to the Hebrews was something over and above [his assigned function.]
Eusebius: the Same.
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, in as much 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.