Don Carson teaches on the importance of obedience to God and his Word as a true demonstration of knowing him, as emphasized in 1 John 2:3–27. Central to the Christian life is having and displaying a genuine love for others, which Carson highlights as a key indicator of living in the light of Christ. He contrasts those who merely talk about faith with those who act on it and discusses the dangers of worldliness versus godliness.

Carson also explores the cultural differences in expressing faith through his observations of diverse groups at Cambridge. He addresses the concept of antichrists and the end times in 1 John 2, urging believers to persevere in their faith and remember their hope in Christ.