The Rapture is before the Tribulation.
2 Thess 2:1-17.
2Th 2:1 Now we beseech you, brethren, by the coming of our Lord Jesus Christ, and by our gathering together unto him, -we speak to you about the coming of our Lord and the Rapture.
2Th 2:2 That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand. -so that you are not troubled thinking as if the Tribulation is about to come upon you.
2Th 2:3 Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition; -dont let anyone deceive you by any means for the day of Christ or day of the Lord i.e. the Tribulation which begins with the Rapture, shall not come until there is an apostasy first and then the Antichrist will be revealed, (see v8 shortly). Church Apostasy predicted: 1 Tim 4:1, 2 Tim 4:3.
2Th 2:4 Who opposeth and exalteth himself above all that is called God, or that is worshipped; so that he as God sitteth in the temple of God, shewing himself that he is God.
-during the Tribulation, the Antichrist will claim to be God and will force all to worship him, and will sit in a rebuilt temple in Jerusalem, Dan 9: 27, Matt 24:15, Dan 11:31
2Th 2:5 Remember ye not, that, when I was yet with you, I told you these things?
2Th 2:6 And now ye know what withholdeth that he might be revealed in his time. -and now you know what is holding back until the Antichrist is to be revealed at the appropriate time..
2Th 2:7 For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way. -for the mystery of iniquity i.e. demonic activity, is already at work (even in Pauls day): only, the Holy Sprit will hinder the level of activity until he (the Holy Spirit) is taken out of the way of it. I.e. at the Rapture the Holy Spirit will leave the earth at the same time as the saints. Then there will be no restraint upon Satans activity.
2Th 2:8 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: -then shall the Antichrist be revealed (i.e. after the Rapture, and the Tribulation is therefore commenced). Whom the Lord shall destroy after the 7 yrs Tribulation at His Second Coming to earth to begin the Millennium, Rev 19:11, 20.
2Th 2:9 Even him, whose coming is after the working of Satan with all power and signs and lying wonders, -the Antichrists coming (i.e. upon approach to being revealed, i.e. present day), is with the work and activity of Satan, with power, signs and signs or miracles.
2Th 2:10 And with all deceivableness of unrighteousness in them that perish; because they received not the love of the truth, that they might be saved. -and with great evil deception in unbelievers (includes false Christians) who are going to hell, because they loved darkness and rejected the truth that could bring them salvation. This is the false revivals today and the alien signs etc.
2Th 2:11 And for this cause God shall send them strong delusion, that they should believe a lie: -in the Tribulation, because men rejected the gospel or didnt truly believe it -they will receive a great deception. Which is probably that the Anti-Christ is Christ and that they should believe this lie which he himself will propagate. This verse refers to the Tribulation and not time before because of Matt 24:11. And the false prophets will prophecy on Antichrists behalf, not for themselves or any other. They will propagate this lie. Christ said that this delusion will be so strong that unless the length of the daylight hours of the Tribulation were shortened, that no man would be saved out of the Tribulation and from this delusional lie, Matt 24: 21-24.
2Th 2:12 That they all might be damned who believed not the truth, but had pleasure in unrighteousness. -this happens for the purpose of condemning those who rejected faith in the truth of the Gospel and the Bible, and who preferred unrighteousness and sin. (Even false doctrine here could be referred to as unrighteousness).
2Th 2:13 But we are bound to give thanks alway to God for you, brethren beloved of the Lord, because God hath from the beginning chosen you to salvation through sanctification of the Spirit and belief of the truth: (-said to true believers..
2Th 2:14 Whereunto he called you by our gospel, to the obtaining of the glory of our Lord Jesus Christ.
2Th 2:15 Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle. -hold fast "don't let go" of the sound interpretations of scripture, -which teaching is still available in the world- though commonly rejected.
2Th 2:16 Now our Lord Jesus Christ himself, and God, even our Father, which hath loved us, and hath given us everlasting consolation and good hope through grace,
2Th 2:17 Comfort your hearts, and stablish you in every good word and work. The true believers ought to be comforted in the truth that they will not have to endure the Tribulation.