Peter turns a corner, rather suddenly and abruptly. From 2:11–3:12 Peter has dealt with one single issue — how to live in the Roman Empire as Christians. Now he faces another problem directly: suffering. And we might be forgiven if we suggest Peter’s opening question borders on the naive. And I hope I’ll be forgiven for suggesting a political application.
“After all,” Peter says, “who will do you evil if you are zealous to do what is good?” Plenty of us would answer back “Plenty of power-mongers would do evil even to those who do good!” It is here that I thinmk the emerging line we are pursuing is so important. But …

First, the “zealous to do what is good” is related to 2:11-12 where doing good is about community beneficence — helping out, building monuments, etc.. And Peter believes in his world that the community will keep its hands off such folks.
Second, Peter is not so naive after all — what he wants (as 3:14 shows) them to know is that they may suffer, and they should not suffer for being doers of bad things but, if they are going to suffer, let it be for doing good things. So, I take 3:13 as a contrast to 3:14 and not a naive question bordering on silliness: the point is not that suffering will never happen for those who do good but that suffering should not be for doing bad things.
Third, Peter’s focus is on Christ: Don’t fear the powerful who oppress; fear the Lord. Keep Christ at the center of your heart.
Application: for years many of us have put up with a measure of suffering for how the USA has presented itself in international relations, and have wearied under the umbrella of many Europeans’ and Middle Easterners’ thinking that these actions are “Christian.” And, frankly, many of us have been far too aggressive in response, far too critical and cranky, and have not been mindful of what Peter says in 3:16: we need to be ready to defend our faith but we are to do so “with gentleness and reverence.” The constant carping I hear, the political slurring, and the facial anger have no place for the Christian who plans a revolution of God’s grace that can transform. Protest, by all means. Revolutionary insubordination, however, does not follow the course of bitter tirades, but of compassionate hope.