2 Thessalonians 2:2

Do not be so easily confused. They were not thinking things through with care. Or upset by the claim. Some had made the claim that the "countdown" for the end of the world had already begun. The Thessalonian church was afraid of what they thought was going to happen! Perhaps this was said. Someone had misunderstood [deliberately?] what Paul had said in his first letter to them. That we wrote this in a letter. It is strongly possible that a forged letter using Paul's name had been circulated, saying the Day of the Lord had come. See note on 2 Thessalonians 3:17.