Suppose you are writing a personal letter to a close friend whom you had not contacted for some time. What would you say? Perhaps you would give him an update on your life, family, and work. But would you warn him to stay away from all sexual sin and live a morally pure life? Would you warn him about God's punishment? Probably not. And you probably wouldn't write to tell him not to commit adultery either, since it would likely be considered out of line.

This is why what Paul writes next is surprising. With strong words and warning of God's judgment, he instructs the Thessalonian believers to stay away from sexual sin of any kind, to control their lusts, and not to harm others by committing adultery (1 Thessalonians 4:3-6).

Such a warning would have been necessary and timely for the church in Corinth because sexual immorality was a major problem there (see 1 Corinthians 5:1-2). But here in 1 Thessalonians, this warning seems out of place and unnecessary. Paul had just commended the believers in Thessalonica for their exemplary and holy lives, calling them ″a model to all the believers in Macedonia and Achaia″ (1 Thessalonians 1:7). So why would he write with such severity?

First, we need to understand the place where the believers lived. Thessalonica was a large and prosperous city plagued by the same social and moral ills that characterise every cosmopolitan city-consumerism, materialistic indulgence, greed, debauchery, lust, prostitution, and sexual promiscuity. Temple prostitution was officially sanctioned by fertility cult religions, giving rise to Thessalonica's notorious and pervasive immorality.⁶ Such were the temptations faced by the Thessalonian believers on a daily basis.

Second, we should recognise Paul's two-pronged approach to teaching in general. On the one hand, he would get involved when things were falling apart, dealing decisively with immediate problems in the church, such as false teachings about Christ's return (see 4:13-18). On the other hand, Paul would also speak when things were going well: ″We instructed you how to live in order to please God, as in fact you are living″ (v. 1). When the believers were on the right path, Paul would challenge them to keep at it-and to do better. Twice, he exhorts them ″to do . . . more and more″ (vv. 1, 10).

Paul's words in today's passage reflect his overall teaching strategy-to teach the whole counsel of God, ″the word of God in its fullness″ (Colossians 1:25). For ″all Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness″ (2 Timothy 3:16).

Paul's approach gives us a pattern to emulate in helping fellow believers to lead worthy lives. Let us teach ″everyone with all wisdom, so that we may present everyone fully mature in Christ″ (Colossians 1:28).