John Calvin Commentary 2 Peter 3:2

"that ye should remember the words which were spoken before by the holy prophets, and the commandments of the Lord and Saviour through your apostles:" — 2 Peter 3:2 (ASV)

That ye may be mindful. By these words, he indicates that we have enough in the writings of the prophets and in the gospel to stir us up, provided we are as diligent as we ought to be in meditating on them. Indeed, when our minds sometimes gather rust or become dimmed by darkness, this is due to our sloth.

So that God may then continually shine upon us, we must devote ourselves to that study. Let our faith, at the same time, rest in witnesses so certain and credible. For when we have the prophets and apostles agreeing with us—indeed, as the ministers of our faith—with God as the author and angels as approvers, there is no reason that the ungodly, all united, should move us from our position.

By the commandment of the apostles, he means the whole doctrine in which they had instructed the faithful.