"Simon Peter, a bond-servant and apostle of Jesus Christ, To those who have received a faith of the same kind as ours, by the righteousness of our God and Savior, Jesus Christ: grace and peace be multiplied to you in the knowledge of God and of Jesus our Lord; seeing that His divine power has granted to us everything pertaining to life and godliness, through the true knowledge of Him who called us by His own glory and excellence. For by these He has granted to us His precious and magnificent promises, so that by them you may become partakers of the divine nature, having escaped the corruption that is in the world by lust."
2 Peter 1:1-4 NASB
When my son and I first started looking over these verses last year, he was unsure how practical the first few verses in 2 Peter would be to his daily life. Why memorize Peter's greeting to his readers? But as we looked at them more closely, it became apparent that this was no casual greeting but a carefully planned reminder of what God has accomplished for every true believer. Before we can delve deeper into the knowledge of God, we have to understand and be certain of where we stand with Him. This is what Peter does in these first few verses.
"There are always those who are ready to help us to yield to doubts and fears and to encourage us in them. I therefore believe, as I am never tired of saying these days, that the first thing that is necessary at the present time is that Christian people should be certain of their position. I borrow the words of the Apostle when he says, 'I will not be negligent to put you always in remembrance of these things, though ye know them'. That is profound psychology! It is a very great mistake to think that because we know a thing we need not be reminded of it repeatedly."
D. M. Lloyd-Jones in Expository Sermons on 2 Peter (Carlisle, PA: The Banner of Truth Trust, 1983), 3.