William Burkitt on 1 Peter 3:14

As if the apostle had said, "Though following that which is good be, generally speaking, a sure and certain way to keep you from harm, yet should it so happen, that notwithstanding all your piety and prudence, you should suffer for well-doing, ye are happy and not miserable; therefore be not afraid of their terrors and threatenings, neither be ye troubled for what they can inflict upon you."

Note hence, 1. That to suffer affliction and persection for righteousness' sake, doth not hinder, but further our happiness; If ye suffer for righteousness' sake, happy are ye, for so suffered your Saviour that went before you.

Note, 2. That when God calls us forth to suffer for righteousness' sake, we must fortify ourselves against all fear: no terrors must trouble us, no apprehended dangers or difficulties must dismay us: Be not afraid of their terror, neither be troubled.