As is well known, the twenty-one letters in our New Testament were selected from a far larger collection of epistles, some of which were early lost, while others, like the Epistles of Barnabas and Polycarp and Clement, were preserved to share with those later accepted as canonical, the study and veneration of the primitive Church. [Sidenote: _Influences that gave rise to the earliest Gospels_] The influences which originally produced the Gospels and Acts were very different from those which called forth the Epistles. The natural preference of the early Christians for the spoken word explains why we do not possess to-day a single written sentence in the Gospels which we can with absolute assurance assign to the first quarter-century following the death of Jesus. Two influences, however, in time led certain writers to record his early life and teachings. The one was that death was rapidly thinning the ranks of those who could say, _I saw and heard_; the other was the spread of Christianity beyond the bounds of Judaism and Palestine, and the resulting need for detailed records felt by those Christians who had never visited Palestine and who had learned from the lips of apostles only the barest facts regarding the life of the Christ. [Sidenote: _Testimony of Luke's Gospel_] The opening verses of Luke's Gospel are richly suggestive of the origin and growth of the historical books of the New Testament: Forasmuch as many have taken in hand to draw up a narrative concerning those matters which have been fulfilled among us, even as they delivered them unto us,--they who from the beginning were eye-witnesses and ministers of the word, it seemed good to me also, having traced the course of all things accurately from the first, to write unto thee in order, most excellent Theophilus, that thou mightest know the certainty concerning the things wherein thou wast instructed. This prologue states that many shorter Gospels had previously been written, not by eye-witnesses, but by men who had listened to those who had themselves seen. Luke leaves his readers to infer that he also drew a large number of his facts from these earlier sources as well as from the testimony of eye-witnesses. The implication of the prologue is that he himself was entirely dependent upon written and oral sources for his data. This is confirmed by the testimony of the _Muratorian Fragment_: Luke the physician, after the ascension of Christ, when Paul had taken him, as it were, as a follower zealous of the right, wrote the gospel book according to Luke in his own name, as is believed. Nevertheless he had not himself seen the Lord in the flesh, and, accordingly, going back as far as he could obtain information, he began his narrative with the birth of John. His many literal quotations from it and the fact that he makes it the framework of his own, indicate that Mark's Gospel was one of those earlier attempts to which he refers. [Sidenote: _Luke's motive in writing_]