Charles Ellicott Commentary 1 Peter 1:15

"but like as he who called you is holy, be ye yourselves also holy in all manner of living;" — 1 Peter 1:15 (ASV)

But as he which hath called you is holy.—More correctly, But according to (or, after, i.e., in the likeness of: see Ephesians 4:24, after God) the Holy One who called you. The “calling” is mentioned because of the obligation it imposes upon us. Bengel notices how fond St. Peter is of the words “call,” “calling.” (See 1 Peter 2:9; 1 Peter 2:21; 1 Peter 3:9; 1 Peter 5:10; 2 Peter 1:3; 2 Peter 1:10.) The “call” here seems to mean specially the call to be children of God.

So be ye holy.—Perhaps the imperative would come out stronger as follows: Do you also show yourselves holy in every part of your conduct. Leighton says, “He has severed you from the mass of the profane world, and picked you out to be jewels for Himself; He has set you apart for this purpose, that you may be holy to Him, as the Hebrew word that signifies ‘holiness’ means ‘setting apart,’ or fitting for a special use; then do not be untrue to His design. It is sacrilege for you to dispose of yourselves after the impure manner of the world, and to apply yourself to any profane use, whom God has consecrated to Himself.”