A rumor had been spreading from false teachers that the rapture had already happened and the Day of the LORD had already begun. The Apostle Paul corrects the false rumor and reminds the Thessalonians that the Tribulation will not begin until the Church is gathered to Christ and then the man of lawlessness (the Antichrist) is revealed. The Church is called to stand firm in their faith as they long for the day of Christ's appearing and look for His return.