1 Peter 3:14

But and if--"But if even." "The promises of this life extend only so far as it is expedient for us that they should be fulfilled" [CALVIN]. So he proceeds to state the exceptions to the promise (Pe1 3:10), and how the truly wise will behave in such exceptional cases. "If ye should suffer"; if it should so happen; "suffer," a milder word than harm. for righteousness--"not the suffering, but the cause for which one suffers, makes the martyr" [AUGUSTINE]. happy--Not even can suffering take away your blessedness, but rather promotes it. and--Greek, "but." Do not impair your blessing (Pe1 3:9) by fearing man's terror in your times of adversity. Literally, "Be not terrified with their terror," that is, with that which they try to strike into you, and which strikes themselves when in adversity. This verse and Pe1 3:15 is quoted from Isa 8:12-13. God alone is to be feared; he that fears God has none else to fear. neither be troubled--the threat of the law, Lev 26:36; Deu 28:65-66; in contrast to which the Gospel gives the believer a heart assured of God's favor, and therefore unruffled, amidst all adversities. Not only be not afraid, but be not even agitated.

— Jamieson-Fausset-Brown Commentary (public domain)