2 Not to allow your minds to be quickly unsettled or disturbed or kept excited or alarmed, whether it be by some [pretended] revelation of [the] Spirit or by word or by letter [alleged to be] from us, to the effect that the day of the Lord has [already] arrived and is here.
3 Let no one deceive or beguile you in any way, for that day will not come except the apostasy comes first [unless the predicted great falling away of those who have professed to be Christians has come], and the man of lawlessness (sin) is revealed, who is the son of doom (of perdition), [Dan. 7:25; 8:25; I Tim. 4:1.]
4 Who opposes and exalts himself so proudly and insolently against and over all that is called God or that is worshiped, [even to his actually] taking his seat in the temple of God, proclaiming that he himself is God. [Ezek. 28:2; Dan. 11:36, 37.]
5 Do you not recollect that when I was still with you, I told you these things?
6 And now you know what is restraining him [from being revealed at this time]; it is so that he may be manifested (revealed) in his own [appointed] time.
7 For the mystery of lawlessness (that hidden principle of rebellion against constituted authority) is already at work in the world, [but it is] restrained only until he who restrains is taken out of the way.
8 And then the lawless one (the antichrist) will be revealed and the Lord Jesus will slay him with the breath of His mouth and bring him to an end by His appearing at His coming. [Isa. 11:4.]