By means of the New Testament Epistles (which are real letters and written with a definite purpose in view) we look directly into the faith, the customs, and practices of the early Christian churches. We see how they were organized and how they conducted their services. We see the marvelous changes wrought in the lives and characters of the converts. We note that the triumphs of faith were won through a belief in the Divine Son of God and the power of the Holy Ghost. The struggles and difficulties of these early Christians in coming out of heathenism are depicted in a masterly way. Paul, in his endeavor to guide aright the churches, of which he had been the spiritual father, shows what he believes and teaches about God, the Holy Ghost, Jesus Christ, sin, redemption, and the future state of the soul. In these letters the incidental and indirect references to the doctrines taught, and the customs of the early churches, are as valuable as the direct. +Some Reasons for Paul's Writings.+--The Apostle was the founder of churches over a large area of territory. He soon realized, however, that it was impossible to visit them as often as he desired and as frequently as he ought. Many of the converts had come out of heathenism and needed doctrinal and ethical instruction in the way of Christ. They also needed encouragement, comfort, and sometimes sharp correction for outbreaking sins. As means of communication were open and easy along the well kept Roman roads, what was more natural than that Paul should begin to write letters which were not only to be read by the particular churches to which they were addressed, but passed on to the other churches. +Qualifications of Paul.+ 1. Intellectual. He was not only pre-eminent as a missionary, but even more remarkable as a writer. "He was the greatest thinker of his age, if not of any age, who in the midst of his outward labors was producing writings which have ever since been among the mightiest intellectual forces of the world and are still growing." 2. Spiritual. He had been converted in a wonderful way and had received a special revelation from Christ (Acts 9:3-15; 1 Cor. 15:3; Gal. 1:11, 12). He had been called to his great work among the Gentiles by Christ and the Holy Ghost (Acts 9:15; 13:2). He was absolutely absorbed in the work of Christ and in making known His gospel. +How the Epistles are Best Understood.+--Each one should be studied in the light of the occasion which called it forth and in connection with the church, group of churches, or the individual to which it is addressed. +Titles and Groups.+--The thirteen Epistles fall naturally into four groups; in each of which is set forth some great doctrinal and ethical truth.