Two letters that Paul wrote to the church in Thessalonica are preserved in the New Testament. The first letter — 1 Thessalonians — was written to a community of believers who had been Christians for only a short period of time, probably no more than a few months. We learn from the Book of Acts that during Paul's stay in the city of Thessalonica, he preached in a Jewish synagogue on three successive Sabbath days. He evidently stayed in the city for some time thereafter and continued his work among the Gentiles. Although his ministry was successful to the extent that he won converts to Christianity from both Jews and Gentiles, he did encounter opposition, especially from Jews who resented very much that he was able to win Jewish followers. Because of this opposition, Paul wisely left the city for fear that the newly formed Christian community would be persecuted as he had been. He regretted that he must leave the Christians before they were well established in the faith, but he hoped that he might visit them again in the near future. When sickness prevented him from returning, he sent his colleague Timothy to strengthen the group and then report back to Paul on the progress that had been made. When Timothy returned to Paul with the good news that the members of the church were standing firm in their new faith, Paul wrote the First Epistle to the Thessalonians.
Paul congratulates the Thessalonians on their fidelity to the gospel that he had proclaimed while among them and urges them to remain steadfast in the faith. He warns them against sensuality and various forms of self-seeking, which are contrary to the spirit of the Christian way of life. But the main purpose of Paul's letter is to deal with a special problem that developed after Paul left the city. Paul shared with the Christians at Thessalonica his belief that the end of the age would come in the very near future. In part an inheritance from Jewish apocalypticism, this belief held that the messianic kingdom would be ushered in by a sudden catastrophic event, at which time the heavenly Messiah would descend on the clouds of heaven with power and great glory. When the first Christians accepted the idea that the man who had died on the cross was the real Messiah, they were convinced that he must return to earth to complete the work that he had begun. The manner of his second coming was conceived in accordance with the apocalyptic conceptions. This belief was common among the early Christians, and Paul accepted it along with the rest. Although the Christians were quite insistent that no one knew the exact time when this second coming would take place, they felt sure that it would occur during the lifetime of those who were then members of the Christian community.
After Paul left Thessalonica, some of the people who belonged to the church died. Because Jesus had not returned, serious doubts arose in the minds of those Thessalonians who were still living, for they had been led to believe that Jesus the Messiah would return before any of them died. As they saw it, Paul was mistaken on this point, which then caused them to wonder whether he might also be mistaken on other points as well. Obviously, an explanation of some kind was in order, and this situation, more than any other single factor, prompted the writing of Paul's First Epistle to the Thessalonians.
In his statement regarding Jesus' second coming, Paul says that he has in no way abandoned his faith that the return of Jesus to this earth will take place in the near future. Concerning those who died or who might die before Jesus returns, he states that they will be raised from the dead and will share equally with those who are still living at that time: "For the Lord himself will come down from heaven, with a loud command, with the voice of the archangel and with the trumpet call of God, and the dead in Christ will rise first." To this statement, Paul adds, "After that, we who are still alive and are left will be caught up together with them in the clouds to meet the Lord in the air. And so we will be with the Lord forever." The letter closes with a reminder that the Day of the Lord will come as a thief in the night. No one knows just when it will come, but all are admonished to live in such a way that they will be ready for it at any moment.
Paul's Second Epistle to the Thessalonians is in one sense a follow-up to the first letter. Evidently, the first letter was well received. People were satisfied with Paul's explanation concerning those who died and were ready and willing to suffer persecution if need be in order to remain true to the gospel that Paul preached. However, some members of the Christian community were so overly zealous about Paul's teaching that the end of the age was near at hand that they stopped making any plans for the future. Indeed, some of them stopped doing any work at all, believing that in this way they were demonstrating their faith in the nearness of the great event. Those who did not work were a burden to those who did work, and this situation constituted a new problem. Paul addresses this concern in his second letter.
After commending the Thessalonians for their loyalty and assuring them that God will deal justly with their persecutors, Paul proceeds to the main point of the letter. Although the coming Day of the Lord is near, it is not as close as some people think. Concerning a report that had circulated among the people stating that the day had already come, Paul tells the Thessalonians not to be deceived on this matter, for the Day of the Lord will not arrive until after certain events have taken place, and these events have not occurred yet. The specific events to which Paul refers concern the coming of an Antichrist, someone in whom the power of Satan has become incarnate and who will establish himself in the Temple at Jerusalem, working with signs and wonders to deceive people. The basis for Paul's statement along this line is found in the Jewish apocalyptic writings, which were fairly well known to him. Concerning the coming of this lawless Antichrist, Paul says that the Antichrist's activities are already in operation and would be carried out more fully except that he is now being restrained. (Presumably, Paul means that the Roman government is restraining the Antichrist.) In due time, the Antichrist will be revealed, and "the Lord Jesus will overthrow [the Antichrist] with the breath of his mouth and destroy by the splendor of his coming." The letter closes with an admonition to the Thessalonians to continue their regular lines of work and not to wait in idleness for the return of Jesus.
The two letters to the Thessalonians are of interest from a historical point of view because they reveal conditions that existed in the newly formed Christian communities. They are also of value in that they indicate something of the extent to which the early church was influenced by Jewish apocalypticism in its beliefs concerning the second coming of Christ and the setting up of the messianic kingdom. Jewish apocalypses taught that there would be a resurrection of the dead in connection with other events that would usher in the new age. Paul was able to make use of these apocalyptic conceptions in answering the questions that so troubled the Christians in Thessalonica.
Both of Paul's letters to the Thessalonians were addressed to this one church and were occasioned by the problems associated with that particular group of church members. It is quite unlikely that Paul anticipated any further use to be made of his letters. Little if anything in them throws much light on the theological issues involved in Paul's interpretation of Christianity. The letters do, however, indicate the type of instruction that Paul gave to newcomers in the Christian movement.