The sermon explores the nature of belief, drawing from John 3:16-18 and Nicodemus's story to distinguish between mere knowledge, mental assent, and genuine trust in Christ. It emphasizes that true belief is a continued state, not a one-time event, and is a gift from God, ensuring that believers will not perish. The message underscores Christ's mission, not to condemn, but to offer salvation through faith, and encourages listeners to persevere in their faith through engagement with Scripture, worship, and prayer, while also boldly proclaiming the gospel to those who are perishing.