Albert Barnes on 1 Peter 3:11

Let him eschew evil. Let him avoid all evil. Comp. Job 1:1.

And do good. In any and every way; by endeavouring to promote the happiness of all. Comp. Gal 6:10.

Let him seek peace, and ensue it. Follow it; that is, practise it. Mt 5:9; Rom 12:18. The meaning is, that a peaceful spirit will contribute to length of days.

(1.) A peaceful spirit--a calm, serene, and equal temper of mind--is favourable to health, avoiding those corroding and distracting passions which do so much to wear out the physical energies of the frame; and

(2.) such a spirit will preserve us from those contentions and strifes to which so many owe their death. Let any one reflect on the numbers that are killed in duels, in battles, and in brawls, and he will have no difficulty in seeing how a peaceful spirit will contribute to length of days.

(*) "eschew" "avoid"