The Second Letter of Paul to the Thessalonians - Introduction
Paul's authorship of 2 Thessalonians has been disputed on several grounds. First, the literary similarities with 1 Thessalonians have suggested to some that an anonymous author, writing in Paul's name, copied from the authentic letter. If, however, one supposes that Paul wrote the second letter very shortly after the first, that hypothesis loses much of its force.
A second and more substantial argument is that in 1 Thessalonians Paul, while emphasizing that the Parousia (see 1 Thess. 2.19 n. ) will come unexpectedly, speaks as if it were near; 2 Thessalonians, on the other hand, indicates that there will be a considerable delay between this letter and the Parousia, and the author gives detailed signs which must occur first. However, these signs are not incompatible with the view that the Parousia will take place within the lifetime of those to whom the apostle writes, or that it will occur unexpectedly even though preceded by such signs.
Third, the strongest argument for inauthenticity is that this letter speaks against the teaching that “the day of the Lord is already here” ( 2.2 ). It is difficult to suppose that this latter view, which treats the Parousia as a present spiritual experience, would flourish in Thessalonica at the same time as the opposite, the fervent expectation of the Lord's coming as a future event, found in 1 Thessalonians. Nevertheless, it is possible that Paul responded to a new problem which arose after the writing of the earlier letter.