Beginning at 1 Peter 2:11, Peter had been instructing his readers on how they were to live as God’s people in a world hostile to God. In the face of public suspicion concerning people whose focus is God’s imperishable inheritance (1 Peter 1:4), Peter stressed the necessity of honourable conduct among the Gentiles (1 Peter 2:12). So Peter spoke repeatedly of doing good (1 Peter 2:12, 1 Peter 2:15, 1 Peter 2:20; 1 Peter 3:2, 1 Peter 3:6, 1 Peter 3:11). Doing good (as opposed to punching back against evildoers, 1 Peter 3:9) may result in suffering. In the present paragraph, Peter sets before his readers what attitude they ought to have in the face of potential injustice. He uses his recent quote from Psalm 34 as a stepping-stone to his further instruction.
13 Now who is there to harm you if you are zealous for what is good?