If holiness is moral perfection, we may well ask what Edwards understood by the beauty of holiness. Beauty is located in God and not in the eye of the believer, although Edwards believed that only the purified eye can apprehend it. In some passages he identifies the beauty of the divine nature with holiness and says that the beauty of the Christian religion resides in its having made holiness the paramount reality.
[Religious Affections (WJE Online Vol. 2) , Ed. Paul Ramsey]