He who hath called you is holy He reasons from the end for which we are called. God sets us apart as a peculiar people for himself; then we ought to be free from all pollutions. And he quotes a sentence which had been often repeated by Moses. For as the people of Israel were on every side surrounded by heathens, from whom they might have easily adopted the worst examples and innumerable corruptions, the Lord frequently recalled them to himself, as though he had said, "Ye have to do with me, ye are mine; then abstain from the pollutions of the Gentiles." We are too ready to look to men, so as to follow their common way of living. Thus it happens, that some lead others in troops to all kinds of evil, until the Lord by his calling separates them. In bidding us to be holy like himself, the proportion is not that of equals; but we ought to advance in this direction as far as our condition will bear. And as even the most perfect are always very far from coming up to the mark, we ought daily to strive more and more. And we ought to remember that we are not only told what our duty is, but that God also adds, "I am he who sanctify you." It is added, In all manner of conversation, or, in your whole conduct. There is then no part of our life which is not to be redolent with this good odour of holiness. For we see that in the smallest things and almost insignificant, the Lord accustomed his people to the practice of holiness, in order that they might exercise a more diligent care as to themselves.

But as he which hath called you is holy - On the word called, see the notes at Ephesians 4:1. The meaning here is, that the model or example in accordance with which they were to frame their lives, should be the character of that God who had called them into his kingdom. They were to be like him. Compare the notes at Matthew 5:48.
So be ye holy in all manner of conversation - In all your conduct. On the word "conversation," see the notes at Philippians 1:27. The meaning is, that since God is holy, and we profess to be his followers, we also ought to be holy.

But as he which hath called you - Heathenism scarcely produced a god whose example was not the most abominable; their greatest gods, especially, were paragons of impurity; none of their philosophers could propose the objects of their adoration as objects of imitation. Here Christianity has an infinite advantage over heathenism. God is holy, and he calls upon all who believe in him to imitate his holiness; and the reason why they should be holy is, that God who has called them is holy, 1-Peter 1:15.

But as he which hath called you is holy,.... Which is a periphrasis of God the Father, who had called them, not merely in an external way, by the outward ministry of the word; but internally, powerfully, and efficaciously, by his Spirit and grace; and who had called them to holiness of life and conversation, as well as in calling had implanted principles of holiness in them, and therefore is said to call them with an holy calling; and who himself is holy, naturally, perfectly, and originally, and in such sense as no creature is, angels or men; and is glorious in holiness, and is the source and fountain of holiness in others: therefore
so be ye holy in all manner of conversation; which respects not internal holiness, but supposes it; for that is God's work, and not the creature's act; it is the sanctification of the Spirit, of which he is the author; this they were chosen unto from the beginning, and made partakers of in regeneration; but external holiness, holiness of life and conversation, in all the parts and branches of it, both with respect to God and men, in matters both of religion and civil life: and to be holy in this sense is an imitating of God, a copying after him, though he is far from being equalled by a sinful creature, or even by an angel in heaven; however, the arguments to it, taken from the nature of God, and of his effectual calling to grace and holiness, are very strong and powerful; for it is walking worthy of him, who has called us to his kingdom and glory; and walking worthy of that calling wherein we are called; and a following of God, as dear and obedient children; and what is according to his will, and what he directs unto, and requires, as appears from what follows.

Literally, "But (rather) after the pattern of Him who hath called you (whose characteristic is that He is) holy, be (Greek, 'become') ye yourselves also holy." God is our grand model. God's calling is a frequently urged motive in Peter's Epistles. Every one that begets, begets an offspring resembling himself [EPIPHANIUS]. "Let the acts of the offspring indicate similarity to the Father" [AUGUSTINE].
conversation--deportment, course of life: one's way of going about, as distinguished from one's internal nature, to which it must outwardly correspond. Christians are already holy unto God by consecration; they must be so also in their outward walk and behavior in all respects. The outward must correspond to the inward man.