Peter argues that, when it comes to living the Christian life, there should be a difference between believers and non-believers. This difference manifests itself in our behavior, our motives and character.
Peter says it is possible to no longer live by human desires but by the will of God (vs. 2). This results in being different from the "Gentiles" who go in for all sorts of debauched and riotous living. Christians are to avoid these excesses and instead practice self-discipline.
Our motivation, then, is do what God wants rather than what our flesh wants. And chief among these actions is to "love one another" (vs. 8). Love covers a multitude of sins - it is an essential practice of the Christian life.
Finally, Peter reflects on the role of suffering for Christians. While both Christians and non-Christians suffer, we should not do so for the same reason. We shouldn't suffer for committing crimes such as murder or theft. Instead, when we suffer because we bear the name of Christ, we will be blessed. This suffering will produce a beneficial result in our character, if we let it, and result in glory for God. May we have the right attitude in this, as in all things we experience in life!