The entire message of 1 Thessalonians 1 could be very well-summarized in the word “sacrifice.” Paul commends these Christians for having “paid the price” in order to become Christians. In verse 6, they had willingly accepted the gospel message, despite opposition. By this, Paul says they had become shining examples not just to other Christians in their own mountainous, poverty-stricken region of Macedonia (northern Greece) but also to the more “well-todo” saints who lived in Achaia, where Athens was located (southern Greece – vs. 7). They had “sacrificed” the idolatry of their former lives to obtain genuine godliness (vs. 9).
Next, notice that in chapter 2 Paul emphasized that the message he had shared with these believers was distinct from both the false doctrines of their former idolatry and from the fraudulent accusations of the “Judaizers” who tried to discredit him by following him from place to place to stir up trouble (vv. 1-4). (Judaizers were people who were trying to make Gentile Christians obey certain aspects of Jewish law, as a condition of salvation.) The contrast between the faulty motives of such false teachers (vv. 2-3) and the gospel (vv. 1 & 4) is the difference between truth and error. Paul stresses the fact that he had been “approved” by God to be “trusted” with the gospel. This means that Paul was speaking with Heaven’s “seal of approval” – and it stands in contrast with the claims and accusations of those who opposed him. Furthermore, he emphasizes here (as in Galatians 1:10) that his goal was to please God, not simply to “tickle the ears” of his hearers for personal profit (cf. 2 Timothy 4:3-4). Through the rest of chapter 2, Paul continues to remind the Thessalonian Christians of how he had behaved while he was with them (humbly, focusing on what would glorify God, vv. 6-8). At verse 13 he pays them a truly high compliment by reflecting on the way they had received the gospel message, pointing out that they had recognized it as God’s own message.
At the end of verse 14, Paul writes something very important, that affect every Christian: In describing the Thessalonians’ willingness to accept the gospel as God’s own word, he goes on to note that it “effectively works” (i.e., “is at work”) within them. This point is important because it draws our attention to the fact that the scriptures are meant to have an ongoing impact in our lives! God’s word is not merely a collection of great literature: Neither is it merely a “good guideline” for our lives. Rather, the gospel is designed to shape, correct, and inspire us to be more like God every day. Paul is commending the Thessalonian Christians because they were allowing it to have this impact in their lives! We do have the ability to resist and ignore God’s instructions – but we do so at our own peril. He gave us the bible to direct and improve our lives in this world so that we can be well-prepared for life in the world to come (cf. 1 Timothy 2:4 – God wants everyone to “come to,” or “arrive at” the knowledge of His truth, and this is what the Thessalonians had done).