John Calvin Commentary 2 Peter 2:19

"promising them liberty, while they themselves are bondservants of corruption; for of whom a man is overcome, of the same is he also brought into bondage." — 2 Peter 2:19 (ASV)

While they promise them liberty. He shows their inconsistency: they falsely promised liberty while they themselves served sin and were in the worst bondage, for no one can give what he does not have. This reason, however, does not seem to be sufficiently valid, because it sometimes happens that wicked men, wholly unacquainted with Christ, preach usefully concerning the benefits and blessings of Christ.

But we must observe that what is condemned here is corrupt doctrine connected with impurity of life, for the Apostle's design was to counteract the deceptive allurements by which they ensnared the foolish. The name of liberty is sweet, and they abused it for this purpose: that the hearer, being released from the fear of the divine law, might abandon himself to unbridled licentiousness.

But the liberty which Christ has secured for us, and which he offers daily by the gospel, is altogether different. For he has exempted us from the yoke of the law insofar as it subjects us to a curse, so that he might also deliver us from the dominion of sin, insofar as it subjects us to its own lusts.

Hence, where lusts reign, and therefore where the flesh rules, the liberty of Christ has no place whatever. The Apostle then declares this to all the godly, so that they might not desire any other liberty than that which leads those who are set free from sin to a willing obedience to righteousness.

From this we learn that there have always been depraved men who made a false pretense to liberty, and that this has been an old, cunning trick of Satan. We need not wonder that today the same filth is stirred up by fanatical men.

The Papists turn and twist this passage against us, but they by this betray their ridiculous impudence. For:

1. Men of the filthiest life, in taverns and brothels, belch out this charge that we are the servants of corruption, though in our lives they cannot point out anything blameworthy.
2. Since we teach nothing concerning Christian liberty except what is derived from Christ and his Apostles, and at the same time require the mortification of the flesh and the proper exercises for subduing it much more strictly than those who slander us do, they vomit forth their curses not so much against us as against the Son of God, whom we have as our certain teacher and authority.

For of whom a man is overcome. This sentence is derived from military law. Yet it is also a common saying among pagan writers that there is no harder or more miserable bondage than when lusts rule and reign. What then should we do, on whom the Son of God has bestowed His Spirit, not only so that we may be freed from the dominion of sin, but also so that we may become the conquerors of the flesh and the world?