2 Thessalonians 2:2
The Thessalonians were being told that the day of the Lord had started in a letter forged as being by Paul. Paul had taught many things to the Thessalonian church within the 1st three weeks of its inception, including the doctrine of the rapture. The Thessalonians were upset that the day of the Lord was at hand and they missed the rapture. The Thessalonians would have no reason to be upset if they had any other rapture view but pre-trib. Paul was pre-trib.