But ye are a chosen generation, a royal priesthood, an holy nation, a peculiar people; that ye should shew forth the praises of him who hath called you out of darkness into his marvellous light: Ye are a chosen generation - The titles formerly given to the whole Jewish Church, i.e. to all the Israelites without exception, all who were in the covenant of God by circumcision, whether they were holy persons or not, are here given to Christians in general in the same way; i.e. to all who believed in Christ, whether Jews or Gentiles, and who received baptism in the name of the Father, and of the Son, and of the Holy Ghost.
The Israelites were a chosen or elected race, to be a special people unto the Lord their God, above all people that were upon the face of the earth, Deuteronomy 7:6.
They were also a royal priesthood, or what Moses calls a kingdom of priests, Exodus 19:6. For all were called to sacrifice to God; and he is represented to be the King of that people, and Father of those of whom he was king; therefore they were all royal.
They were a holy nation, Exodus 19:6; for they were separated from all the people of the earth, that they might worship the one only true God, and abstain from the abominations that were in the heathen world.
They were also a peculiar people, λαος εις περιποιησιν, a purchased people; סגלה segullah, a private property, belonging to God Almighty, Deuteronomy 7:6; none other having any right in them, and they being under obligation to God alone. All these things the apostle applies to the Christians, to whom indeed they belong, in their spirit and essence, in such a way as they could not belong to the Hebrews of old. But they were called to this state of salvation out of darkness - idolatry, superstition, and ungodliness, into his marvellous light - the Gospel dispensation, which, in reference to the discoveries it had made of God, his nature, will, and gracious promises towards mankind, differed as much from the preceding dispensation of the Jews, as the light of the meridian sun from the faint twinkling of a star. And they had these privileges that they might show forth the praises of Him who had thus called them; αρετας, the virtues, those perfections of the wisdom, justice, truth, and goodness of God, that shone most illustriously in the Christian dispensation. These they were to exhibit in a holy and useful life, being transformed into the image of God, and walking as Christ himself walked.