The Thessalonians were "shaken in mind" and "troubled" (2 Thessalonians 2:2), but they had already been taught about this. Paul's question gently reminds them that nothing he is saying is new. Barnes explains that Paul refers them back to what he had told them about the great apostasy "to show that his views had not changed." Gill reads the question as a mild rebuke for forgetting what they had heard. Matthew Henry says Paul had told them "with design, no doubt, that they should not take offence nor be stumbled at it."

Paul does not wait for an answer. He continues, "And now ye know what withholdeth that he might be revealed in his time" (2 Thessalonians 2:6), building on what they already know. He assures them that the Lord will destroy the wicked one "with the brightness of his coming" (2 Thessalonians 2:8), gives thanks that God chose them to salvation (2 Thessalonians 2:13), and ends, "Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle" (2 Thessalonians 2:15).

Paul's first visit to Thessalonica was short: he reasoned in the synagogue "three sabbath days" before trouble forced him to leave (Acts 17:2, 10). Even so, Barnes notes that the second coming "seems to have constituted an important part of the instructions of Paul when at Thessalonica." In the Greek, the verb for "told" (elegon) is in the imperfect tense, a form often used for ongoing or repeated action in the past, so the sense can be "I was telling you." Gill offers two readings of Paul's warning about a letter "as from us" (2 Thessalonians 2:2): a forged letter falsely claiming to come from the apostles, or Paul's former letter wrongly represented or not understood.

Paul's answer to fear is memory. Before he gives more teaching, he sends the Thessalonians back to what God had already given them through his preaching. False alarms lose their power when believers remember what they have been taught.

The passage also shows that God's plan is not out of control. The "man of sin" will be revealed "in his time" (2 Thessalonians 2:6), and the Lord will destroy him "with the brightness of his coming" (2 Thessalonians 2:8). Paul's calm reminder rests on God's sure timetable. That is why he can say, "stand fast" (2 Thessalonians 2:15).