After his introduction, Peter begins by writing that Christianity may not be easy. Though the believer is overjoyed at the assurance of heaven, yet still, he may experience different kinds of trials in this life. These will come in order to prove his belief genuine to the glory of God. 

There are two sides two every trial. On the one hand, God is seeking to prove the believer's faith genuine. On the other, Satan is tempting the believer in the hopes of turning him against God.