Within a short time of sending off 1 Thessalonians, Paul received news that certain Christians in the Thessalonian church had misunderstood parts of the letter. He therefore sent off the letter known to us as 2 Thessalonians. Paul was still in Corinth (he remained there a year and a half; Acts 18:11), and his second letter may have followed his first by only a few weeks.
One misunderstanding of the Thessalonians concerned the return of Jesus Christ. Paul had said that Christ would return unexpectedly and suddenly, but some people thought this meant he would return immediately. There were even those who thought that if this were the case, there was no purpose in working any longer. As a result they became idle and a burden to others (2 Thess 2:1-2; 3:11). In writing to correct the misunderstandings, Paul gave additional teaching about the return of Christ, rebuked those who were idle, and gave further encouragement to those who were persecuted.