Why does Paul mention the man of sin in 2 Thessalonians 2?
Paul mentions the man of sin because, though his letters focus on the church rather than prophecy itself, the church is approaching prophecy's fulfillment. As it bumps against that door, Paul gives statements in 2 Thessalonians 2 about this coming man who will rule during the Tribulation.
Les explains that Paul never writes about prophecy per se, because Paul writes concerning the church. But as the church bumps right up against the door of the fulfilling again of prophecy, Paul makes statements in II Thessalonians chapter 2 concerning this man of sin. In that context, Les is describing the attributes or personality of the man who will come on the scene to rule the world during the Tribulation, after earlier coming out of Daniel and moving into the New Testament for those descriptions.