2 Peter 1:1-11 (ESV)
Simeon Peter, a servant and apostle of Jesus Christ,
To those who have obtained a faith of equal standing with ours by the righteousness of our God and Savior Jesus Christ:
 May grace and peace be multiplied to you in the knowledge of God and of Jesus our Lord.
 His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence,  by which he has granted to us his precious and very great promises, so that through them you may become partakers of the divine nature, having escaped from the corruption that is in the world because of sinful desire.  For this very reason, make every effort to supplement your faith with virtue, and virtue with knowledge,  and knowledge with self-control, and self-control with steadfastness, and steadfastness with godliness,  and godliness with brotherly affection, and brotherly affection with love.  For if these qualities are yours and are increasing, they keep you from being ineffective or unfruitful in the knowledge of our Lord Jesus Christ.  For whoever lacks these qualities is so nearsighted that he is blind, having forgotten that he was cleansed from his former sins.  Therefore, brothers, be all the more diligent to make your calling and election sure, for if you practice these qualities you will never fall.  For in this way there will be richly provided for you an entrance into the eternal kingdom of our Lord and Savior Jesus Christ.
Second Peter also falls into the category of anti-legoumena. That is people really aren’t sure if Peter wrote it or not. Yet it is helpful reading even if it can’t be used to seat doctrine.
Peter stas this letter out with a more or less standard greeting, and then a bit of admonition. After telling us that we have been given, or granted all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence, he tells us to make use of them.
We have been given gifts, all that pertain to godliness and life. Peter here says those who fail to use these gifts are nearsighted, and have forgotten that he has been cleansed of former sins. Forgiveness in other words, is not an excuse to continue sinning. It is true that we will continue to sin, and will continue to be tempted to sin, and will probably find ourselves failing often in making use of the gifts and virtues that Jesus has given us. But each and every day as we drown the Old Adam in repentance remembering the promises the Christ made to us in the baptismal flood, saving us from our sins, we once again pick up the gifts and make use of them best we can. We have been cleansed of our former sins, even the ones that are former by a nano second. Yet it isn’t an excuse to sin. We have been cleansed. Why do we want to return? We don’t want to be the sow returning to wallow in the mud. And it is possible for us to rid ourselves of some particularly destructive sins and practice a bit of self-control. Not that we earn salvation thereby, but that thereby we learn to enjoy the life that has been given to us. We share the faith with others by showing in our action the value of the life that we have all been given in Christ, value that teaches us to love, not as we love ourselves, but as we have been loved by the savior who died that our sins would be forgiven.