Holy, holy, holy cry the angels around the throne of God. Isaiah’s vision of God, recorded in the sixth chapter of his prophecy, is a vision of the Holy One of Israel. Holiness is a characteristic of God. The root idea of holiness is separation. The holy is the separate, the distinct, the different.

The separation of true holiness has three key dimensions. The first is separation from the world. The vision of God in Isaiah 6 is a vision of God in His temple. The temple expressed for Israel separation from the world. He alone is God, separated from the world in His transcendent glory.

We need reflect on the call to holiness as a call to avoid worldliness. Many surveys in our time have shown that we spend our money, divorce our spouses, and raise our children very much as the world does. Are we, then, “a holy priesthood and “a holy nation” (1 Peter 2:5. 9) as Christ calls us to be?

Second, God is holy as exalted one. “I saw the Lord seated on a throne, high and exalted.” God not only is separated from the world, but He is highly exalted over it. His holiness is unique in that only He is Almighty, only His glory fills the whole earth.

The holy exaltation of God should lead us to respond as Isaiah did in the presence of God. He cried, “Woe to me! I am ruined.” Isaiah was humbled by the greatness of God. As we understand the holiness of God, we will be overwhelmed by our smallness and insignificance next to the Almighty. If the holy angels cover their eyes in His presence, how much more must we humbly bow before Him?

Third, God is holy in His goodness. The Holy One of Israel is altogether pure. All His being and doing are righteous and clean. There is no sin in Him. As the Reformed confessions declare, even in His complete sovereignty He is not the author of sin, the very idea of which is blasphemy. He is holy in being, wholly good.

Isaiah, in the presence of God's Holiness, recognized his own sinfulness. He cried, “I am a man of unclean lips and live among a people of unclean lips.” He uses the language of skin disease to describe his sin. In his repentance, God forgives him, cleanses him, and fits him for service. Isaiah is made to be a saint, a holy one of God.

In the New Testament, Christians often are called saints. By the work Jesus Christ we are forgiven and renewed as His holy people. By the one Isaiah called “the holy seed” (Isa. 6:13) we are made holy. Jesus Christ is “our righteousness, holiness and redemption” (I Cor. 1:30). When we are forgiven and renewed in Jesus, then we can begin to understand and respond to the call of God, “Be holy because I, the Lord your God, am holy.”