John Gill expounds on 2 Peter 2:20, emphasizing that individuals may escape the corruptions of the world and exhibit outward reformation without possessing true grace. He warns that a mere acknowledgment of Christ, devoid of genuine spiritual experience, can lead to a superficial faith that ultimately results in a worse state than before. Gill illustrates that those who return to worldly sins after such a reformation face greater condemnation due to their prior knowledge and profession of faith. The sermon highlights the dangers of false security in external righteousness and the necessity of true transformation through Christ.