The major issue most Christians note with regard to these two epistles is their similarity. Giese notes the parallels (4), explains the common theories (4ff), and concludes that Peter drew on Jude (6) and likely had a different secretary for 2 Peter than he did for 1 Peter (8, 2).
To him who is able to preserve you as unstumbling and to present (you) in the presence of his glory as blameless with great exultation, to the only God, our Savior, through Jesus Christ our Lord be glory, majesty, power, and authority before all time, now, and for eternity. Amen. (355)
Look for new volumes in Concordia Commentary soon, including 1-3 John, Romans 1-8, and Mark 1:1-8:26.