What does 1 Thessalonians 3:3 mean?

Timothy's presence and preaching at Thessalonica would stabilize the believers and keep them from falling victim to the pressures of persecution. This was the reason Paul was willing to be left alone, sending Timothy to these Christians for their own support (1 Thessalonians 3:1–2). Paul reminds his readers, in this verse, that afflictions are a normal part of the Christian's experience. According to later verses, Timothy's visit was also to see if the Thessalonians had been able to endure their trials (1 Thessalonians 3:5).

In 2 Timothy 3:12 Paul assured Timothy that "all who desire to live a godly life in Christ Jesus will be persecuted." Writing to the Corinthian church, Paul assured his readers that God uses trials to advance the gospel and to help believers look beyond temporal afflictions to eternal things (2 Corinthians 4:8–18). Paul's faith and hope were so strong that in 2 Corinthians 4:17 he calls his afflictions "light" and "momentary." He lists his trials in 2 Corinthians 11. They include imprisonments, beatings, perilous escapes from persecutors, forty lashes less one, three beatings with rods, multiple brushes with death, stoning, shipwreck, being adrift at sea, danger from robbers and angry Jews and Gentiles, danger in the city, danger in the wilderness, danger at sea, danger from false brothers, toil and hardship, sleepless nights, hunger and thirst, cold and exposure. Paul also includes that he has daily pressure over his concern for the churches.

Paul's focus to this point has been on praising the Christians of Thessalonica for their faithfulness and growth. This change in tone, it seems, is more meant as encouragement than as criticism.