2 Peter 3:1-2

The doctrines and precepts delivered by the prophets and apostles, being the most effectual means of preserving the Christian converts from being seduced by the false teachers spoken of in the preceding chapter, the apostle begins this with informing the brethren that his design in writing both his epistles was to bring these doctrines and precepts to their remembrance. And as one of the greatest of these men's errors was their denying the coming of Christ to judge the world, and destroy this mundane system, he first exhorts the brethren to recollect what the holy prophets had anciently spoken on this subject, together with the commandments of the apostles of Christ to their disciples, to expect and prepare for these events. His saying, This second epistle I now write, &c., implies that he had written a former one to the same people, and he here affirms that in them both he had one great end in view, which was to stir up their minds (which he terms pure, or rather sincere, as ειλικρινη more properly signifies) to keep in remembrance and lay to heart what had been already taught them on these important subjects, so as to be properly influenced by it. The holy prophets intended, who had spoken of these things, were chiefly Enoch, mentioned Judges 1:14; David, Psalms 50:1; Psalms 75:8; and Daniel 12:2.