v1-10 - The purpose of Peter's letters (and all of the books of the Bible, for that matter) is "to stimulate you to wholesome thinking (v1)." Peter lists three ways for you to do this:
v2 - Recall the words of scripture;
v3-7 - Be aware the world is full of scoffers who "deliberately forget (v5)" who God is and what He's done;
v8-10 - In contrast to the scoffers, you must not forget God's patience.
v11-16 - How should you live knowing that the world will "disappear with a roar," "be destroyed by fire," and "be laid bare?" You ought to:
v11 - "Live holy and godly lives," looking forward to the Lord's return;
v14 - "Make every effort to be found spotless, blameless, and at peace with him."
v17-18 - Peter closes this short letter with two more imperatives:
"Be on your guard;"
"Grow in the grace and knowledge" of Jesus.
In general, we are not people who like to wait. Ironically, although it seems like Christ's second coming is the ultimate thing you must wait for, it's not included in the list of things Peter tells us to do. Waiting is the ultimate passive waste of time, but yet so many people, including Christians, live as if life i