1 Peter 4:12

The frequent repetition of counsel and comfort to Christians, considered as sufferers, in every chapter of this epistle, shows that the greatest danger these new converts were in arose from the persecutions to which their embracing Christianity exposed them. The good behaviour of Christians under sufferings is the most difficult part of their duty, but yet necessary both for the honour of Christ and their own comfort; and therefore the apostle, having extorted them in the former part of this chapter to the great duty of mortification, comes here to direct them in the necessary duty of patience under sufferings. An unmortified spirit is very unfit to bear trials. Observe, I. The apostle's kind manner of address to these poor despised Christians: they were his beloved, Pe1 4:9. II. His advice to them, relating to their sufferings, which is, 1. That they should not think them strange, nor be surprised at them, as if some unexpected event befell them; for, (1.) Though they be sharp and fiery, yet they are designed only to try, not to ruin them, to try their sincerity, strength, patience, and trust in God. On the contrary, they ought rather to rejoice under their sufferings, because theirs may properly be called Christ's sufferings.

— Matthew Henry's Concise Commentary (public domain)

strange--they might think it strange that God should allow His chosen children to be sore tried. fiery trial--like the fire by which metals are tested and their dross removed. The Greek adds, "in your case." which is to try you--Greek, "which is taking place for a trial to you." Instead of its "happening to you" as some strange and untoward chance, it "is taking place" with the gracious design of trying you; God has a wise design in it--a consolatory reflection.

— Jamieson-Fausset-Brown Commentary (public domain)