Beloved, do not be surprised at the fiery trial when it comes upon you to test you, as though something strange were happening to you. But rejoice insofar as you share Christ’s sufferings, that you may also rejoice and be glad when his glory is revealed.” (1 Peter 4:12–13, ESV)

Suffering and trials should not surprise us.  This is the lot of followers of Christ on this earth.  It is not strange or unusual, it is to be expected.  The world does not want to hear the message of Christ, men prefer to continue in their sins and evil is evil.  This all leads to suffering for those who proclaim Christ.

What surprises the reader here is what Peter tells us to do about suffering.  Run?  Hide?  Return evil for evil?  No.  We are to rejoice because our suffering for following Jesus means that we are sharing in Christ’s sufferings which will ultimately lead to gladness and rejoicing when Jesus’ glory is fully and finally revealed, when evil is conquered and when Satan is tossed into the abyss.

The Bible Knowledge Commentary points out here:

“The New Testament is clear that those who take part in the suffering of Christ also will take part in His glory, when it is revealed (apokalypsei; cf. 1 Peter 1:7; 5:1). Peter presented this truth as a cause for future hope and present rejoicing while enduring persecution.”