What Is Love and What Is Not Love explores the biblical definition of love, contrasting God’s perfect love with the distortions of sin. It begins by explaining that God Himself is love, and His love is revealed through Jesus Christ and expressed in how believers are called to love one another. The chapter provides a list of God’s kind of love and guidance on how Christians should respond to His love and commandments so they may grow in it as God intended. It then examines the opposite—what is not love—through a biblical commentary that highlights 100 sinful behaviors and attitudes the New Testament warns against, showing that continuing in unrepented sin contradicts genuine love. Readers are reminded that repentance is essential, since sin is not love and destroys true fellowship with God and others. The chapter stresses that love is essential to salvation, and a lack of love exposes hypocrisy or lukewarm faith. It also addresses the reality of temptation, evil, and satanic opposition, clarifying that though these forces attempt to draw believers away, nothing can ultimately separate God’s people from His love in Christ Jesus. Assurance of salvation is tied to authentic love, distinguishing true Christians who abide in God’s love from false ones who do not. Finally, the chapter calls believers to return to their first love in Christ, reaffirming that prayer and repentance are vital to remaining rooted in God’s love and bearing fruit that reflects His nature.