1 Thessalonians 4:1-8

v1-2: "We must not only persevere [in the faith] to the end; we should become even better and walk even more consistently and closely with God."  God is pleased when we make progress in holiness and pleasing God "should be the aim and goal of every Christian."  This means we need to be taught not only what to believe but also how to live.

v3-5: All kinds of sexual immorality, "either in the married or unmarried state," are sins that are directly opposed to sanctification or the holy life we are to live as followers of Jesus.  It is God's will for our lives that we keep our bodies pure from defiling sinful desires and do not indulge them.  We are not to behave like those who don't know God or Jesus as their Saviour.  Purity in heart, speech, and behaviour, is "one thing that God commands in his law and that his grace brings about in all true believers."

v6: "The sin of sexual immorality, especially adultery, is a great act of injustice that God will punish."  Adultery and other acts of sexual immorality not only pollute the soul and body of the person who is guilty of this, it is act of injustice to others, "especially to those joined together in the marriage covenant forever."  Christians are to flee from all forms of sexual immorality for their good and the good of others.

v7-8: "The Holy Spirit is given to us to protect us against these sins and help us to put to death these acts of the body, so that we may live."