Although the original readers of Peter’s letter were experiencing relatively mild opposition from their neighbors, in I Peter 3:8-22, he wanted to prepare them for worse persecution to come and the unfair suffering they would have to endure.  As in all the letter, God calls on us both to preach and to practice what we preach, no matter how others might be treating us.  In fact, when we endure unfair suffering as Christians, we receive special blessings and opportunities to demonstrate our faith.