This section opens and closes with explicit references to the will of God.
4:3-5 The will of God for the Christian is clear. Positively it is sanctification, namely a life set apart from sin unto God. Negatively it involves abstinence (self-denial) from all kinds of sexual behavior that is outside the prescribed will of God including adultery, premarital sex, homosexuality, etc. Rather than participating in these acts the believer should learn how to control his or her body and its passions in sanctification and with honor. We should not behave lustfully as Gentiles who do not have special revelation of God and His will. The Greeks practiced sexual immorality commonly and even incorporated it into their religious practices.
"Chastity is not the whole of sanctification, but it is an important element in it . . ."66
Another less probable interpretation of "possess his own vessel"(v. 4) sees the vessel as the wife of the addressee.67This view takes ktasthai("possess") as "acquire,"its normal meaning, and skeuos("vessel") as "wife."68Loosely interpreted Paul then meant that men were to live with their wives in a way that would not strain their marital relationship (cf. 1 Pet. 3:7). However, Paul used skeuosof one's own body elsewhere (Rom. 9:22-23; 2 Cor. 4:7; cf. 1 Sam. 21:5), and ktasthaican refer to one's treatment of himself or herself as well as one's wife.
4:6 Sexual immorality is wrong not only because it transgresses the will of God, but because it injures the partner in sex. It brings God's judgment down on two people, not just one, and it defrauds the partner of God's blessing. Paul probably had the Lord's future judgement of believers in view rather than His present discipline (cf. 2:19; 3:13; 1 Cor. 3:10-17).
4:7 The general principle the Thessalonians were to keep in mind was that God's purpose for all Christians is not impurity but purity. It is a life set apart from sin unto holiness.
4:8 To reject these exhortations amounted to rejecting God, not just the Apostle Paul. Lest someone think that this standard is impossibly high, Paul reminded his readers that God has given His Holy Spirit to all believers to enable us to do God's will (cf. Gal. 5:22-23).
"While Paul deals with sexual immorality in other letters, most notably 1 Cor. 6:12-20, nowhere does he employ such coercive language to enforce proper Christian conduct. The serious and even threatening tone of vv. 6-8 suggests very strongly that Paul was dealing with a problem that had actually emerged in the community at Thessalonica and that he viewed with considerable concern."69
