The essential attribute of God by which He is utterly set apart from all that is creaturely, sinful, or common — and the derived quality produced in believers as they are conformed to His character. In God, holiness is not one virtue among many but the totality of His moral perfection and otherness: it is what makes Him God. In believers, holiness is the fruit of the Spirit's progressive work of sanctification — a real, practical separation from sin and conformity to the character of Christ. Without holiness, no one will see the Lord (Heb 12:14).
HO'LINESS, n. The state of being holy; freedom from sin and sinful affections; sanctity. In a moral sense, applied to God, it denotes perfect moral purity, and entire freedom from all sin and moral imperfection. Applied to men, it denotes conformity in heart and life to the moral character of God; true piety and moral virtue. Also: used as a title of the Pope. The holiness which God requires is conformity of heart and life to his revealed will and character.
Modern Christianity has largely replaced holiness with niceness, tolerance, and therapeutic comfort. "Holy" is reduced to a soft synonym for "religious" or used ironically ("holy cow"). The biblical call to be holy as God is holy is dismissed as legalism or religious rigidity. Culture reframes holiness as judgmentalism — the one who calls sin "sin" is called hateful, while the one who embraces all behavior is called loving. The radical demand of God's holiness — and the terror it rightly produces in sinners — is almost entirely absent from contemporary preaching.
• Leviticus 11:44 — "I am the LORD your God; consecrate yourselves and be holy, because I am holy."
• Isaiah 6:3 — "Holy, holy, holy is the LORD Almighty; the whole earth is full of his glory."
• 1 Peter 1:15–16 — "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.'"
• Hebrews 12:14 — "Make every effort to live in peace with everyone and to be holy; without holiness no one will see the Lord."
• Revelation 4:8 — "Holy, holy, holy is the Lord God Almighty, who was, and is, and is to come."
H6944 — qōdesh (קֹדֶשׁ): holiness, set-apartness; the fundamental attribute of God's transcendent otherness from creation and sin.
G38 — hagiasmos (ἁγιασμός): sanctification, holiness; the state and process of being set apart for God's exclusive purposes.
G40 — hagios (ἅγιος): holy, set apart; used of God, angels, Scripture, and believers consecrated to God.
• "The thrice-repeated 'Holy, holy, holy' in Isaiah 6 is the only divine attribute so emphasized in Scripture — holiness is the crown of all God's perfections."
• "Holiness is not primarily about behavior; it is about belonging — you are holy because you belong to the Holy One, and your behavior should reflect that reality."
• "A church that does not pursue holiness has confused the comfort of the Gospel with the demand of the Gospel."