And if it be further urged that these writers would have referred more frequently to the Gospels, had they really known them, we must remember that their writings are generally short; and while a single quotation proves the previous existence of the document quoted, ten pages without a quotation do not disprove it. Moreover when they refer to the sayings of Christ, or the events of His life, they always do so without the slightest hesitation; as if everyone acknowledged them to be true. And as we have seen, their allusions often begin with the words _remember_ or _be mindful of_, clearly showing that they expected their readers to know them already. Hence some books must then have existed which were well known, containing a life of Christ; and the improbability of these having perished, and a fresh set of Gospels having been published in a few years, is very great. And the evidence in regard to the _Third_ Gospel is particularly strong, since it was addressed to Theophilus, who was clearly a prominent convert; and he must have known from whom the book came, even if for some reason this was not stated in the heading. And as he is not likely to have kept it secret, the authorship of the book must have been well known to Christians from the very beginning. Therefore the testimony of early writers, like Irenæus, who always ascribed it to St. Luke, becomes of exceptional value; and makes it almost certain that he was the author. We may now sum up the _external testimony_ to the Four Gospels. It shows that at the _beginning_ of the second century they were well known to Christian writers, and this alone would necessitate their having been written in the first century, or at all events before A.D. 110. And thanks to modern discoveries, especially that of the _Diatessaron_, this is now generally admitted. It may indeed be considered as one of the definite results of recent controversies. But if so, it is, to say the least, distinctly probable that they were written by the men to whom they have been universally ascribed. We have thus strong external testimony in favour of the genuineness of the Four Gospels. CHAPTER XV. THAT THE GOSPELS ARE GENUINE FROM INTERNAL EVIDENCE. (_A._) THE FIRST THREE GOSPELS. (1.) Their general accuracy; this is shown by secular history, where they can be tested. (2.) Their sources; the triple tradition; other early documents. (3.) Their probable date; before the destruction of Jerusalem, A.D. 70. (_B._) THE FOURTH GOSPEL.