"Therefore, prepare your minds for action; be self-controlled; set your hope fully on the grace to be given you when Jesus Christ is revealed. As obedient children, do not conform to the evil desires you had when you lived in ignorance. 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."
The Greek word for holy: hágios – properly, different (unlike), other ("otherness"), holy; for the believer, (hágios) means "likeness of nature with the Lord" because "different from the world."
The meaning of the Hebrew word qadosh literally means "to be set apart for a special purpose".
The primary meaning of holy is ‘separate.’ It comes from an ancient word that meant, ‘to cut,’ or ‘to separate.’ Perhaps even more accurate would be the phrase ‘a cut above something.’
What does it mean that God is holy? It means that God is absolute perfection. God is unlike any other and His holiness is the essence of that! His very being is completely absent of even a trace of sin. He is high above any other and no one or anything can compare to Him. God’s holiness permeates His entire being and shapes all His attributes. His love is a holy love, His mercy is holy mercy, and even His anger and wrath are holy in nature. When God told Israel to be holy in Leviticus 11:19, He was instructing them to be distinct from the other nations by giving them specific regulations to govern their lives. Israel is God's chosen nation and God has set them apart from all other nations. They are His chosen people, and they were given standards that God wanted them to live by so the world would know they belonged to Him. When Peter repeats what God said in 1 Peter 1:16, he is talking specifically to believers. As believers, we are called-out from the world. We are to be living by God's standards, not the world's. God isn't calling us to be perfect, we are made perfect (a continual process in Christ), but to be distinct from the world. 1 Peter 2:9 describes believers as "a holy nation." We are separated from the world; by the blood of Christ, we need to live that reality in our lives daily.
Holiness is not something that we will possess as a natural part of our nature; we only become holy when we enter into relationship with Christ. It is an imputed holiness. Only in Christ do we “become the righteousness of God” (2 Corinthians 5:21). God’s holiness is more than just His perfection or sinless purity; it is the essence of His divine existence. God’s holiness embodies the mystery of His awesomeness and causes us to gaze in wonder at Him as we begin to comprehend just a little of His majesty. With these thoughts in mind, we begin to see how much more God is asking of us than mere morality. As long as our notions of holiness are limited to doing certain things and not doing other things, we can go through our entire lives obeying the rules (or at least maintaining the appearance of doing so) without dealing with far more fundamental questions: Whose are we? To whom do we give our first love and loyalty?
God's call to be holy is a radical, inclusive claim on our lives, and our identities. To be a disciple of Jesus Christ requires nothing less than death to our fallen, self-centered selves in order that we might live in and for him. "For whoever wants to save his life will lose it," says Jesus, "but whoever loses his life for me and for the gospel will save it. What good is it for a man to gain the whole world, yet forfeit his soul?" (Mark 8:35-36). To be holy means that all we are and all we have belongs to God, not ourselves, and that every aspect of our lives is to be shaped and directed toward God.
"Be holy, because I am holy," says our Lord. Holiness is not primarily about moral purity. It's primarily about union with God in Christ and sharing in Christ's holiness. Only Christ-centered holiness will safeguard us from the trap of moralism and help us maintain our spiritual footing.
Let us be mindful of the importance of this divine attribute and consider the response which this truth should produce in our lives as we seek to worship and serve Him. Holiness only results from a right relationship with God by believing in Jesus Christ as Savior (accepting His gift of eternal life). If we have not placed our faith in Him (the Son of God), then our pursuit of holiness is in vain; you must be born again! If we truly are believers, then we recognize that our position in Christ automatically sets us apart from the world (1 Peter 2:9).