1Th. 4:1 Finally, brothers and sisters, we ask and urge you in the Lord Jesus that, as you learned from us how you ought to live and to please God (as, in fact, you are doing), you should do so more and more. 2 For you know what instructions we gave you through the Lord Jesus. 3 For this is the will of God, your sanctification: that you abstain from fornication;
The church at Thessaloniki was made up of mostly non-Jews, so Paul knew that it was important to teach them about sexual purity, because that was not something that was expected in their society. As Demosthenes wrote:
“We keep mistresses for pleasure, concubines for our day-to-day bodily needs, but we have wives to produce legitimate children and serve as trustworthy guardians of our homes.”
This attitude was not acceptable to God’s people. In Acts 15, when the leaders of the Jerusalem church welcomed the Gentile Christians into the body, they thought it important to remind them to abstain from fornication (Acts 15:29).
We live in such a world today. How do we make moral decisions? As we continue in this chapter we will see three more important points, but Paul begins with what we have been taught. In understanding right from wrong, the most important thing is to know what God has said. Paul writes that they have been taught to abstain from fornication, meaning every type of sexual sin.