The sermon addresses the persistent threat of false teaching within the church, drawing from passages in 2 Peter and highlighting examples throughout the New Testament, including Galatians, Colossians, and Ephesians. It emphasizes that while the gospel offers freedom through grace, this can be twisted into a license for evil, particularly through denial of fundamental truths and a rejection of Christ's authority. The speaker underscores the importance of recognizing the influence of natural minds and the necessity of both the Word of God and the Holy Spirit to combat doctrinal error and preserve the integrity of the church, ultimately affirming Christ's promise that the church will endure despite these challenges.