One of the basic features of the Christian life is separation from the world. Not isolation from the world–refusal to engage with people outside the bubble of church and family life–but separation from the world–refusal to be worldly. We are called to be holy; holy means set apart by God, for God, and thus reflective of God’s character.
When the apostle Peter wants to express this to the churches, the ‘elect exiles’ living as strangers in this world, he first draws attention to the future, where their hope lies: “Therefore, with minds that are alert and fully sober, set your hope on the grace to be brought to you when Jesus Christ is revealed at his coming” (1 Pet. 1:13). This fallen world, with its perilous pleasures, is not where our hope lies. Our hope is wrapped up in the blessed return of our Lord, and the promise of a new world where His kingship will be fully realized. We live as citizens of that new world, even while we live in this one.
Then the apostle turns attention to the past, to emphasize the contrast in life before and after conversion: “As obedient children, do not conform to the evil desires you had when you lived in ignorance” (v.14). The Christian life is supposed to be different from life apart from Christ. Now that we know our heavenly Father, we ought to live differently than we did before. Holiness is implied by adoption into the family of God.
What defines this difference? The character of God our Father. “But just as he who called you is holy, so be holy in all you do; for it is written: ‘Be holy, because I am holy'” (vv.15-16). Those who have been set apart by the Holy One are called to be holy.
This is not a regrettable consequence of Christianity. The pursuit of holiness is one of the blessings of salvation. Those who are united with Christ have been made holy in Him, and are called to be holy by the Holy One who has called them His own. The challenge for the church in our time is to embrace this sacred blessing for what it is, and walk in the blessed holiness we have been given.