--V.3 "that day [from v.2, NOT the event from v.1] will NOT be present if not shall have come THE DEPARTURE *FIRST* [the noun-event from v.1] and [distinctly] the man of sin be revealed..."
I suspect you may be cutting and pasting. The caps, brackets, bolds, etc. make your reasoning hard to follow. Using phrases instead of 'v.1' make the argument easier to follow. I find myself having to go through the verses and reconstructing which one is which verse in my head. Just sayin.
Why should I believe 'the departure' refers to the rapture instead of what Paul calls 'the departure' elsewhere-- some departing from the faith? I see no reason to jump on the pre-trib train of circular reasoning unless there is solid evidence. Where is the evidence for either a 7-year second coming or two second comings (pariousia's)? In this very chapter, the man of sin is destroyed at the brightness of his coming in verse 8.
II Thes.
8 And then shall that Wicked be revealed, whom the Lord shall consume with the spirit of his mouth, and shall destroy with the
brightness of his coming:
9 Even him, whose coming is after the working of Satan with all power and signs and lying wonders
Why would that be a different coming/parousia, than the one in verse 1
1 Now we beseech you, brethren, by the
coming of our Lord Jesus Christ, and by our gathering together unto him,
Notice the gathering here associated with the Lord's parousia, as it is at the
end of the tribulation in Matthew 24. He mentions the parousia first, then the gathering, which we both take to refer to the rapture.
Compare this to Paul's previous letter, I Thessalonians, Paul had written to them about events that occurred at the coming of the Lord, as we read in chapter 4.
15 For this we say unto you by the word of the Lord, that we which are alive and remain unto
the coming of the Lord shall not prevent them which are asleep.
16 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and
the dead in Christ shall rise first:
17 Then we which are alive and remain shall be
caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.
Paul uses a definite article, 'the coming' of the Lord, not 'a coming of the Lord. τὴν παρουσίαν
Why would Paul use the same words, teach on the same subjects, but be using the words with different definitions just to fit the pretrib theory which was developed in the 1800's? Why should I believe that without some actual evidence from scripture of pretrib that does not consist of 'spinning' a passage so it could possibly fit with pre-trib as you are doing here?
Why would I think that the 'departing', defection or apostasy Paul writes of here refers to the rapture. Greek speakers relatively early on. Chrysostom in his Homily 3 on the book associated the departure with the deceptions of the Antichrist. Matthew 24 warns of the love of many growing cold, deception from false prophets and false Christs.
Why would the Greek word which you translate 'departure' be different from how Paul used it elsewhere in his writings?
I Timothy 4:1
Now the Spirit speaketh expressly, that in the latter times some shall
depart from the faith, giving heed to seducing spirits, and doctrines of devils;
Why should I turn the interpretation of Paul's writings on it's ear to accomodate pre-trib. "Here parousia means this. There parousia has a different definition and means that. Here the departure is a bad thing. There it is the rapture." That's spinning interpretations of passages to fit a preconceived notion. It is called eisegesis, not exegesis.
So the DEPICTION of this looks like the following:
[X='you are here'...THEN "first vertical line is 'arrow UP' [='THE Departure *FIRST*']"..<then DOTL will be in existence on the earth w/its 'man of sin' (SEAL #1) and 'judgments' unfolding>... THEN "second vertical line is Jesus' "RETURN" to the earth ('arrow down') FOR the earthly MK age (note: the DOTL continues clear throughout the MK age also [including both "DARK/IN THE NIGHT" (red) as well as the FULL LIGHT OF DAY (purple)])]
-----X---l_<DOTL>__________l______________<1000y>_______________>
V.3 - "that day [the DOTL time period] will not be present, if not shall have come THE Departure FIRST, and [distinctly] the man of sin be revealed..."
(and he is revealed at the START of the 7-yrs [2Th2:9a/8a], not at its MIDDLE [2Th2:4 (not depicted in this illustration)], nor at its END [2Th2:8b])
Why don't you re-write this stuff in plain English without the distracting brackets, colors, etc.?
Chapter 1 refers to 'that day'-- the day when Jesus comes back and executes wrath on them that believe not. Why wouldn't that be the same 'day of the Lord' in the next chapter. If you argue that 'the day of the Lord' can take more than 24 hours...okay... but that is not reason to think that the coming of Christ, the very event the chapter is discussing is excluded from the day of the Lord.
[the "24 elders" (representing "the Church which is His body") are shown to be in heaven BEFORE the opening of SEAL #1 when Jesus will "STAND to JUDGE" [Isa3:13, Rev5:6, etc]... and they SAY in Rev5:9 "us/we"--"we shall reign on the earth"... just like Rev1:5-6 had said "us"--they are wearing "stephanos/crowns" and Paul had been told he would receive a "stephanos/crown" IN THAT DAY (note: the DOTL [earthly] and the Day of Christ/-our Lord Jesus Christ run CONCURRENTLY, but in distinct LOCATIONS, and with distinct PURPOSES)]
John saw the elders in heaven way back when... whenever Revelation was written. It might have been in the 90's AD. Unless you are arguing that the rapture happened before that, I don't see how this proves much along the lines of the timing of the rapture. From Paul's writings, we can see that it happens at the parousia, and that that wicked will be destroyed at the brightness of His parousia.
If He does not come here, how is that a parousia?