The second letter to the Thessalonians was written by Paul about the same time as the first letter - A.D. 51. In it the apostle continues to thank God for these Christians and to assure them of his prayers.
As he spoke about the coming of Christ, "parousia", which is "the rapture", in the first letter, here he speaks of the revealing of Christ, "apokalupsis", which is the second coming of Christ on "the Day of the Lord" as found in Revelation 19. Paul taught the coming of the Lord to this young church. In fact, nowhere else in the Pauline corpus are these teachings found. They are truly unique to the Thessalonian correspondence. Otherwise, general instruction on godly living is offered.