based on his promise

Peter, like many believers must have felt that He was living in the end times.  Christian persecution was intensifying.  Circumstances from town to town were highly uncertain.  The church was advancing and churches were being built.  When he wrote 2 Peter, his attempt was to encourage the believers who were scattered around the world about the truth of Christ's return.  The thing I love about this book is Peter's reference to the promises of God.  It's quite a statement.   Christian hope is based on the promise. 

But based on his promise, we wait for new heavens and a new earth, where righteousness dwells.(2Pet. 3:13 )

Our hope is certain, based on His promise.  Praise God!