John Gill expounds on 2 Peter 2:21, emphasizing that it would have been better for those who have known the way of righteousness to remain in ignorance than to turn away from the truth they once embraced. He explains that the knowledge of the Gospel, which leads to justification through faith in Christ, carries a greater responsibility and guilt when rejected. Gill highlights the danger of apostasy, where individuals who once followed the holy commandment of the Gospel return to their former sinful ways, thus aggravating their condition. The sermon warns against the serious consequences of turning away from the truth after having known it.

Ver. 21. For it had been better for them,.... Not that ignorance is good, or to be excused; but it would have been a lesser evil, and not so much aggravated: not to have known the way of righteousness; the same with "the way of truth", 2Pe 2:2, and "the right way", 2Pe 2:15, the Gospel, which points out the way and method of a sinner's justification before God, which is not by the works of the law, but by the righteousness of Christ imputed to them, and received by faith; and which teaches men to live soberly, righteously, and godly; and a large, notional, though not an experimental knowledge, these apostates had of the word and doctrine of righteousness, and indeed of the whole of the Christian religion, which may truly go by this name: than after they have known [it]; owned, embraced, and professed it: to turn: the Vulgate Latin version, and some copies, as the Alexandrian and others, add, to that which is behind; to their former lusts, or errors, or worse, which they had turned their backs upon externally: from the holy commandment delivered unto them; by the commandment is meant the Gospel also, see 2Pe 3:2; called holy, because of its nature and influence, and in opposition to the pollutions of the world; and which is the faith once delivered, Jude 1:3, and which they received, as delivered to them; and, particularly, the ordinances of it, which they once submitted to, kept, and observed, as they were delivered to them, but now relinquished, or corrupted: wherefore, it would have been better for them to have been in their former ignorance, either in Judaism, or in Gentilism, since proportionate to a man's light is his guilt, and so his punishment, see Ro 2:12.