D.L. Moody emphasizes the importance of living in full communion with God, urging believers to allow God to influence every aspect of their lives, from daily habits to conversations. He warns that even small distractions can hinder this communion and encourages Christians to prioritize Christ in their hearts. Moody illustrates that just as a small insect can thrive in polluted waters by gathering a protective layer of air, believers can shield themselves from the world's negativity through prayer and communion with God. He reminds us that true Christianity is the manifestation of Christ in our daily lives, as exemplified by Daniel's purity in Babylon.