What does 1 Thessalonians 4:3 mean?

After celebrating the faith of the Thessalonian Christians, Paul has transitioned to encouragement and teaching. He has motivated them to continue doing good and even to increase their efforts (1 Thessalonians 4:1–2).

Here, Paul declares that God wants believers to be holy and separated unto Him. He commanded His people Israel, "Consecrate yourselves . . . and be holy, for I am the LORD your God" (Leviticus 20:7). The Lord has also summoned Christians to be holy. Peter writes, "As he who called you is holy, you also be holy in all your conduct" (1 Peter 1:15).

One means of remaining holy is to avoid sexual sin. The Greek word porneia, translated "sexual immorality," is a general term that includes extramarital sex, homosexuality, and premarital sex. The Thessalonian believers lived in a pagan culture in which sex outside marriage was often considered an act of worship, one that honored Greek gods. For example, in Corinth a temple dedicated to the goddess of love was served by more than a thousand prostitutes.

Paul's readers had turned to the true God and away from false gods (1 Thessalonians 1:9). Now Paul reminds them to keep away from every form of sexual sin, no matter how acceptable it might be to their culture (1 Thessalonians 4:5).