For the Christian confession, the doctrine of the Trinity makes all the difference in the world, for that doctrine is at the heart of the Christian gospel, and so at the heart of the Christian understanding of the nature of God and of the manner of God’s relation to the world. The doctrine of the Trinity is the Christian understanding of God; and so the doctrine of the Trinity shapes and determines the entirety of how we think of God’s nature, including how we think of God’s holiness. In short: God is holy as Father, Son and Spirit.