The word holy has more than one meaning. It can mean to be set apart as for a sacred purpose or it can mean to be morally pure. Of course, God qualifies as both. He is set apart from all other beings by His transcendence and greatness (Exodus 15:11; Jeremiah 10:6) and He is morally pure by His goodness and righteousness (Habakkuk 1:13; Psalm 7:11). God is holy in a way that no other being is holy. The prophet Isaiah and the apostle John both emphasize this point by way of repetition (Isaiah 6:3; Revelation 4:8). God is not only holy; He is holy, holy, holy! Only God Himself is inherently holy. Holiness is an attribute of His very essence and being. Each Person of the Godhead (Father, Son, and Holy Spirit) is holy. It is only through God's grace and the humility of Jesus Christ that we are able to share in His holiness (1 Corinthians 1:28–31; 2 Peter 1:3–4).
Is being holy even possible since only God is holy?
Not only can we be holy but we must be holy if we ever hope to see God (Hebrews 12:14). In one sense of the word, all Christians are already holy in that we have been sanctified [made pure; cleansed] by the sacrifice of Jesus' body and blood, which expiates our guilt and covers our sins (Hebrews 10:10; 13:12). This holiness has to do with our status before God. Although we still have and struggle with a sin nature, the blood of Christ covers our sins so that God views us as holy in Christ. This holiness status is not something we have earned but is a status conferred on us when we receive the Holy One of God, who is Jesus Christ (John 6:69; Luke 1:35; Hebrews 7:26; Revelation 3:7). Those who receive Jesus Christ not only have their sins forgiven, but also are credited with the righteousness of Christ. Again, when God looks at the Christian He sees the righteousness of Christ which has been reckoned to the believer (Romans 3:22; 4:5).
The status of holiness is different from the pursuit of holiness. Although believers in Christ have already been sanctified as regards our status before God, we are also called to engage in the process of sanctification. This is the process whereby our characters are progressively conformed to the likeness of Christ experientially and not in status only (2 Corinthians 3:18; Romans 8:29). In other words, we are called to live up to our status (1 Corinthians 1:2). However, we are not called to do so in our own power. It is by the power of the indwelling Holy Spirit, who is given to everyone who believes, that we pursue our sanctification (Philippians 2:12–13). Sanctification is a lifelong process which is never complete until we are glorified (i.e. made perfect and unable to sin). We are not glorified until we die and go to be with God or until Christ returns (Romans 8:30; 1 John 3:2–3).
Finally, Christians are also referred to in Scripture as holy because we have been set apart from the rest of the world. We have been chosen by God to be His special possession (1 Peter 2:9). We have been separated from the anti-God mindset and lifestyle which is embraced by the world (Romans 12:2; John 17:16). We have been set apart to live godly lives and do good works (2 Timothy 2:21; Ephesians 2:8–10). We have a special purpose and a sacred mission. We have received the holiness which belongs to Christ, we are pursuing that holiness by being progressively conformed to His image, and we are declaring the gospel of God's Holy One to the world. All this we do for the glory of God alone. The One who is thrice holy and who reigns forever.
What is holiness according to the Bible? How can I be holy?
What does the Bible mean when it calls something sanctified?
Is entire sanctification possible? Can Christians achieve sinless perfection in this life?
How are Christians not of this world?
What does holy, holy, holy mean in reference to God?
Truth about the Christian Life