2 Thessalonians 2 is often referenced to refute a pre-trib rapture, but this passage does the opposite, it supports pre-trib rapture.
2 Thessalonians 2:1-3 KJV
1) Now we beseech you, brethren, by the coming of our Lord Jesus Christ, and by our gathering together unto him,
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.
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;
There is the gathering unto the Lord, and there is the day of Christ/day of the LORD (depending on your ms.). These are two different things.
If they were in fact the same thing, why would the people be troubled over some one saying "that day is now here"? Check the wording and grammar.
What Paul is saying here is, don't be troubled concerning our being gathered to Jesus because someone is telling you the day of the Lord is here. That day, the day of the Lord, won't come until these other things happen first.
Ergo:
These things haven't happened, so you can know the Day of the Lord is not here. So that being the case, don't be troubled concerning your being gathered to Jesus.
Ask yourself, if the rapture of the church and the Day of the Lord are the same thing, why would they be troubled at someone saying "the day of the Lord is here". The wording "is at hand" is from the Greek enestiken, which is the Perfect Tense for "has in stood", which is to say, "It's arrived, and is here." If they thought that these were the same thing, this would be understood as someone telling them, "It's Rapture Day!"
Don't be worried about being raptured to Jesus, just because someone is telling you "it's the Day of the LORD". Because it's not. The prerequisites haven't happened yet.
2 Thessalonians 2:1-3 KJV
1) Now we beseech you, brethren, by the coming of our Lord Jesus Christ, and by our gathering together unto him,
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.
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;
Much love!