I. The first part of this second Epistle aims at widening the view of the Thessalonian converts into the future the future bliss of believers, the future doom of the rebellious. The second part, embraced in this chapter, seeks to guard them beforehand against delusion as to the nearness of that future, and the mischief which the cherishing of such delusion would produce. The Apostle wishes them to be forearmed by being forewarned. His chief design is to impress upon their minds the one truth, that the proper attitude to be assumed towards the day of the Lord is that not of idle curiosity, but of steadfast and untroubled faith. The spirit of restless eschatological excitement meets, sooner or later, only with disappointment. It brings with it no increase of joyful hopefulness; it rather ministers ultimately to the service of the world. Whatever be the value of Apocalyptic study, it must ever, as these Epistles themselves so strikingly illustrate, find its balancing and regulating principle in the study of Christian ethics, and in the homage of Christian work.
II. The day of the Lord will not be "except the falling away come first." Chrysostom curiously says, "He calls Antichrist himself the apostasy, as being about to destroy many, and make them fall away." But obviously this apostasy is rather that which is simply to precede and usher in the revelation of the great Apostate himself, "the man of sin." He is described not as an ideal, but as an historical personage the man who is regarded as the very embodiment of all evil the hideous consummation and manifestation of all that sin can make man. Depravity is in him personified. The sanctuary or inmost shrine, in which he is to take his seat, is not to be explained with rigid literalness as referring to the temple of Jerusalem. We must regard it as representing the Church of Christ not any material structure, such as St. Peter's at Rome, but the universal company of professed believers. "He sets himself forth as God." It is the act of one who, while he is, as never man was before, the representative of evil, represents himself in his own person and deeds, as the individual manifestation of Divine power and grace.
J. Hutchison, Lectures on Thessalonians,p. 280.
Reference: 2 Thessalonians 2:3-10. Homilist,vol. vi., p. 392.