Approximately one third of the New Testament consists of letters, or epistles, written by the apostle Paul and addressed to the Christian churches of his day. Because these letters are older than any of the gospel accounts of the life of Jesus, they constitute the most reliable source that we have today for information concerning the early history of the Christian movement. With few exceptions, these letters were written in response to conditions that existed in the particular churches with which Paul was associated. Not until some time passed after Paul's death were these letters circulated among the churches and read along with the Old Testament Scriptures as a part of regular worship services. Still later, they came to be regarded as inspired writings comparable to the sacred Scriptures of Judaism.
To understand the contents of these letters, it is necessary to know something about the man who wrote them, as well as about the particular circumstances under which they were written. Fortunately for us, considerable information along these lines is available within the letters themselves and can be supplemented by biographical accounts written by Luke, who was a companion of Paul, and included in the Book of Acts.
Paul was a native of Tarsus, a city of considerable importance in the Greco-Roman world. He was a descendant of the Hebrew tribe of Benjamin and originally was named Saul, after Israel's first king. Raised in a Jewish home, he was taught the Old Testament Scriptures and brought up in strict accordance with the beliefs and practices of the Pharisee sect. As he grew older, he was sent to the city of Jerusalem, where he studied under Gamaliel, one of the leading Jewish rabbis of that day. Later, he returned to Tarsus and probably attended the Greek university located in that city, although we have no direct information about this.
A crucial turning point in Paul's career came after he returned to Jerusalem and began studies in preparation for becoming a rabbi. As a devoted and loyal Jew of the Pharisee sect, his attention was given primarily to a detailed analysis of the requirements set forth in the Mosaic Law. He became familiar not only with the Law itself but with the explanations and commentaries made by the leading rabbis of the Jewish faith. In harmony with one of the basic doctrines of Judaism, he believed that salvation could be obtained only by obedience to all of the laws that God had given to his people. But as Paul pursued his studies, he became conscious of the fact that a mere knowledge concerning what one ought to do does not produce the desire to do it. Furthermore, he realized that desires give rise to actions, but the Law is unable to give one the desires that are necessary to meet its requirements. In fact, the situation is even worse than that, for the knowledge that one ought not to do certain things often acts as a stimulus creating the desire to do it. This conflict between duty and desire became an intolerable situation for Paul; because of it, he gave up his plans for becoming a rabbi. To compensate for his failure to carry out his original plans, he was anxious to find something of real merit that he might do, which he believed he found in the need for suppressing a new religious movement that he regarded as both dangerous and heretical — Christianity.
This new religious movement was promulgated by a group of people who claimed to be followers of Jesus, a man who had been crucified but who, they now believed, had risen from the dead, ascended to heaven, and would return to earth in power and great glory. Putting an end to this movement was what Paul now devoted himself to with the utmost zeal. He hunted down the members of this group, had them committed to prison, and threatened them with death. But as he did so, he could not help but be impressed by the way in which the Christians met the persecutions inflicted upon them.
The stoning of Stephen was one of these incidents. With perfect calm and an inner peace of mind, Stephen knelt down and prayed that those who were casting the stones might be forgiven. It was perfectly evident that these Christians possessed that which Paul desired more than anything else: the peace of mind that comes with a clear conscience and a deep conviction that they are living in harmony with the will of God. Paul came to realize that there must be some connection between these persons' faith in Jesus and their manner of living. No doubt this conviction was growing upon him for some time, but the climactic turning point in his career came while he was journeying to Damascus. Convinced now that Jesus was a righteous man and that his death on the cross was not the just punishment of a criminal but rather that of a martyr who died for a noble cause, Paul was ready to give himself to that same cause, which was more alive than it had been before Jesus' crucifixion and which pointed the way to a salvation that could not be achieved by obedience to a set of laws that were contrary to human desires.
Paul's decision to cast his lot with the members of the Christian community did not make him a missionary all at once, for about fourteen years passed before his work as a leader in the movement received any general recognition. During this time, Paul had ample opportunity to rethink his religious conceptions, systematize his understanding of the meaning of Jesus' career on earth, and formulate plans for spreading Christianity throughout the world. Eventually, he was invited by Barnabas to come to the church at Antioch and assist in the work being done there. After serving this church for a brief period, Paul began a series of missionary journeys to spread the news of salvation offered through Jesus' physical death. While engaged in these missionary activities, he wrote the letters that are preserved in the New Testament.