2 Thessalonians 2:3

let no man beguile you in any wise: for it will not be, except the falling away come first, and the man of sin be revealed, the son of perdition,

There is no hint here regarding the length of the time interval between the time Paul wrote and the actual coming of Christ in the Second Advent. In the light of intervening events, we now know that centuries and millenniums of time were to elapse before the final judgment; but as regards the actual date, we are no better off than were they. The event is still scheduled for a time yet future; and, as the mystery of lawlessness was working then, so it is now; but no man can know how long it will be before the Lord comes.

The man of sin ... See excursus on this at the end of the notes on this chapter. He is the same as the "lawless one" in 2 Thessalonians 2:8, with this distinction, that "the man of sin" refers to a progressive development of an anti-Christian influence, whereas "the lawless one" is thought by many to refer to some terminal and final embodiment of evil. The interpretation presented here is that the man of sin has indeed appeared. The man of sin sitteth in the temple; he exalts himself; he is a false apostle, the son of perdition; names of blasphemy are upon his head; and he is drunken with the blood of the martyrs of Jesus; but his course is not yet run. The final usurpation of the place of God himself has not yet taken place.

The son of perdition ... Judas is the only other person so designated in the New Testament. Just as he was the object of prior prophecy, so also is the apostle of apostasy.