What does 2 Thessalonians 2:2 mean?
Paul urges his readers not to let false teachings about the day of the Lord upset them or cause them to be afraid. They were to reject false teaching, whether it came by prophecy, a report, or a letter. Paul had already explained truths about these things to the Thessalonians (1 Thessalonians 1:10; 4:13–17; 5:1–11), but they were now experiencing doubts.Some who taught error about the day of the Lord claimed to have received the teaching directly from God. Some said they heard it from one source or another. In addition, the church must have received the teaching from a letter that bore a counterfeit of Paul's signature. Specifically, the false teaching alleged that the day of the Lord had arrived.
In his first letter the apostle John urges believers not to "believe every spirit, but test the spirits to see whether they are from God, for many false prophets have gone into the world" (1 John 4:1). John's advice parallels Paul's advice to the Thessalonians. Today, we must compare religious teachings with the teaching of Scripture, if we wish to enjoy peace of mind and spiritual balance.