II Peter 2:19-20.
While they promise them liberty, they themselves are the servants of corruption: for of whom a man is overcome, of the same is he brought in bondage.
For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning.
Untangling the pronouns will help us to understand more clearly what Peter is saying. I’ve looked in several commentaries, and in several versions, and here is what I have concluded:
The first they in v. 19 refers to false teachers who promise liberty to them, those whom they teach; and often convince that they do not need to live holy in Christ, but are free to live however they please. The irony here is, of course, that the false teachers are themselves servants of corruption as they gather fame and fortune for themselves, thereby becoming servants to what they teach.
New converts (they have escaped the world’s pollution through knowledge of Christ) become tangled up in the screed of the false teachers. Believing they are hearing something new and never before understood in Christianity, they become worse in their behavior than they were before they believed in Christ.
This passage has often been used to teach that people who follow false teachers were either never truly saved, or that they can lose their salvation by turning away from a holy life. I believe there is more credence in the idea that they were never truly born again than that anyone can lose his salvation simply by how he chooses to live. If the latter were true, then we would all be in danger every single day that we live.
We are sinful people, by nature. Even the great Apostle Paul battled just as we do. In Romans 7:21-25 we read about his struggle, which should be familiar to anyone who is honest about his own propensity to sin. The bottom line here is that we do not gain or lose salvation by the way we live. Salvation belongs to God, Who bestows it upon those who believe in Him and receive His gift of eternal life through the blood of Jesus.
When we are born again, we are sealed by the Holy Spirit (Eph. 6:1). His presence in our lives brings an awareness of sin, and a sense of shame when we indulge in sin. It is possible, however, for us to quench the Spirit (I Thess. 5:19) when we choose to continue our sinful behaviors. Thus, we need to always be on guard against the blandishments of false teachers, who are themselves in bondage to corruption.