The first-century Christians in Thessalonica heard false charges against the Apostle Paul that he was one of the many religious teachers of that era who said what people wanted to hear in order to enrich himself. Unsurprisingly, then, Paul includes in his first letter to the Thessalonians a defense against such charges. He reminds them that the accusations could not stick because he did not flatter them or demand their financial support when he ministered to them (1 Thess. 2:1–9). In fact, Paul lived among them as an example of righteousness and blamelessness (v. 10).
Yet, the Apostle served not merely as an example but as an instructor, as we see in today’s passage. Paul notes that he was like a father and the Thessalonians his children, for he exhorted them “to walk in a manner worthy of God, who calls you into his own kingdom and glory” (vv. 11–12). Several things are worth highlighting here. First, Paul clearly refers to moral instruction—“a manner worthy of God.” God’s Word commands parents, particularly fathers, to make sure that children learn the Scriptures, especially its eternally valid moral principles (Deut. 6:6–7; Prov. 1:8–9; Eph. 6:4). Paul delivered this moral teaching to the Thessalonians as a whole and as individuals. He taught “each one”; that is, he offered some guidance to each person in his specific situation.
Second, given that Paul ministered in Thessalonica for only three weeks or so, this moral teaching was delivered at roughly the same time as or immediately after his preaching the gospel (Acts 17:1–4). Moral instruction could not be delayed but had to take place right away, which shows that the Christian ethic is inseparable from the Christian gospel. Lose one, and the other will disappear as well.
Third, Paul indicates that living the Christian ethic is “worthy of God” (1 Thess. 2:12). Essentially, the Apostle means that believers must live in such a way that it can rightly be said of them that they belong to God. In other words, our conduct must reflect the character of God Himself. If it does not and we remain impenitent, we show ourselves unworthy of the kingdom. The sense here is not that we merit our kingdom citizenship by our holiness but that kingdom citizenship inevitably and always manifests itself by our holy living. Paul says that we are to “walk” in such a way, using the present tense (v. 12). We should be consistently pursuing righteousness, slowly but steadily increasing in godliness.