What does it mean that God is holy?
Answer
Holiness is probably the least understood attribute of God in popular Christianity, and yet it is the one that the heavenly beings around His throne cry out about continuously: "Holy, holy, holy is the Lord of hosts; the whole earth is full of his glory." (Isaiah 6:3). Not "love, love, love." Not "grace, grace, grace." Holy.
The Hebrew word qadosh — holy — means to be set apart, to be other, to be distinct. At its most fundamental level, God's holiness means He is utterly unlike anything in creation. He is not just the biggest or most powerful thing in existence. He is in a completely different category.
This has two dimensions. First, God's transcendent otherness — His absolute uniqueness, His infinite difference from everything created. When Isaiah saw the Lord "high and lifted up" (Isaiah 6:1), he did not respond with wonder and admiration. He responded with terror: "Woe is me! For I am lost; for I am a man of unclean lips, and I dwell in the midst of a people of unclean lips; for my eyes have seen the King, the Lord of hosts!" The holiness of God undoes you.
Second, God's moral purity — His complete and absolute separation from all sin, evil, and corruption. Habakkuk 1:13 says God is "of purer eyes than to see evil and cannot look at wrong." God is not merely better than us morally — He is infinitely, categorically pure in a way that makes all human goodness look threadbare by comparison.
Why does this matter? Because holiness is the lens through which every other attribute of God must be understood. His love is holy love — not sentimental indulgence. His wrath is holy wrath — the necessary reaction of infinite purity to moral evil. His grace is holy grace — not cheapness, but the gift of the holy God who paid an infinite price to make unholy people holy.
And the goal of the Christian life is spelled out in 1 Peter 1:15-16: "As he who called you is holy, you also be holy in all your conduct, since it is written, 'You shall be holy, for I am holy.'" We are being made like the God we worship.
Isaiah 6:3, 1 Peter 1:15-16, Habakkuk 1:13, Revelation 4:8