This passage is one of the most difficult in the New Testament. The difficulty comes in our not knowing the oral teaching of Paul, who had already spoken to the Thessalonians about the subject (2:5). So, let us instead focus on what we can know.
First, the Thessalonians were challenged in their understanding of Christ’s second coming. Some thought it to be imminent (2:2), though the letter was written at an early date (about 51 AD).
Second, Paul assured them that the day of Christ was not yet present, because two events would have to happen before its occurrence. One, a falling away. (There have been numerous apostasies since the writing of this passage). Second, the revelation of the “man of sin”, the “son of perdition.” (While it is difficult to say who this is, it can again be said that many individuals through the last two centuries can be described in this way). (2:3-4)
So, while it is difficult for us to understand exactly what these two events are, there is no reason to think that the events are still in the future. The Lord has not come, but He could at any time (2 Peter 3:8-13).
