These verses are the beginning of two chapters of practical instructions as Paul explains the behaviour-patterns which please God.  He covers intimate relationships (1 Thessalonians 4:3-8), relationships in the church (1 Thessalonians 4:9-10), in the workplace and community (1 Thessalonians 4:11-12), and personal lifestyle (1 Thessalonians 5:1-28).  The context for this teaching is not the rigours and perils of persecution, but the anticipation of Jesus coming again – encouraging them to look ahead to be ready for an eternity with Jesus (1 Thessalonians 4:13-18).

Even though the Thessalonians were brothers and sisters to Paul, he was still their apostle, teacher and mentor.  Jesus had appointed him, because the new churches would only know how to live holy lives in an unholy society if they were told what did and what did not please the Lord (Ephesians 5:10).  The pressures of the world, the frailty of the flesh and the active deceptions of the devil were constantly trying to pull the believers away from sound teaching.  That is why Paul did follow-up visits to the churches or sent people from his team to reinforce the teaching - encouraging believers not just to hear the Word but to do it (James 1:22-25).
 
Although some academics like to teach that the Bible is just like any other book, to be criticised, to extract the parts they like and discard what they dislike, Paul claimed a different authorship for his writing - the Lord Jesus Christ.  What Paul preached and wrote was not his invention, reflecting his view of the world.  It was the Lord Jesus who personally instructed him about the timeless principles of living in His kingdom (Galatians 1:11-24).
 
This is important information for us who live many years after the Bible was written.  What we read is not a collection of Paul's ideas: they are God's instructions (1 Thessalonians 2:13).  Matters of sexual purity, responsibility to the global church, everyday business practice, the Second Coming, respect for church leaders, work ethics, and arguments between believers, are all instructions from Jesus.  We cannot divide our lives into an inner sacred faith and everyday secular life, or church life and work life.  We only have one life, the Christian life, if we are following Christ.  And all of that life needs to be informed by His Word.  And if you find Word@Work or any other Bible teaching helpful - pray to desire what God says, learn to do it in His strength, and dare to share it in His power … until He comes!