INTRODUCTION TO 2 PETER:
As the Christian movement gained steam, churches began to encounter more false teachers in their midst. Second Peter was written to warn about one of these groups—people who were essentially saying that Jesus would not return, so they could live any way they liked. Against this view, 2 Peter argues that the Day of the Lord is surely coming, and that believers should live in light of this truth.
Taken from the Holy Bible, New Living Translation for ease of reading: