Peter calls this his second letter, written to stir up sincere minds by reminding them of the words of the holy prophets and the commandment of the Lord and Savior through the apostles. He warns that in the last days mockers will come, walking after their own desires, and saying, Where is the promise of his coming? For, from the day that the fathers fell asleep, all things continue as they were from the beginning of the creation. Peter says they willfully forget that the heavens and the earth were formed by the word of God, and that the world of that time was destroyed by water.
Peter answers the mockers with the character of God. But don’t forget this one thing, beloved, that one day is with the Lord as a thousand years, and a thousand years as one day. The Lord is not slow concerning his promise, as some count slowness; but he is patient with us, not wishing that anyone should perish, but that all should come to repentance. What looks like delay is mercy.
Still, the day of the Lord will come as a thief in the night. Present things will not last. So Peter asks what kind of people believers ought to be, and answers: holy and godly. They look for new heavens and a new earth, in which righteousness dwells, and should be diligent to be found in peace, without defect and blameless. Peter notes that Paul wrote of these things too, though some twist hard passages. He closes, But grow in the grace and knowledge of our Lord and Savior Jesus Christ. To him be the glory both now and forever.