It is not a brilliancy which dazzles, but a delicate whiteness and a brilliancy infused, furnishing the most excessive delight to the eyes, never wearied thereby, nor by the visible brightness which enables us to see a beauty so divine.  It is a light so different from any light here below, that the very brightness of the sun we see, in comparison with the brightness and light before our eyes, seems to be something so obscure, that no one would ever wish to open his eyes again.  It is like most pellucid water running in a bed of crystal, reflecting the rays of the sun, compared with most muddy water on a cloudy day, flowing on the surface of the earth.  Not that there is anything like the sun present here, nor is the light like that of the sun: this light seems to be natural; and, in comparison with it, every other light is something artificial.  It is a light which knows no night; but rather, as it is always light, nothing ever disturbs it.  In short, it is such that no man, however gifted he may be, can ever, in the whole course of his life, arrive at any imagination of what it is.  God puts it before us so instantaneously, that we could not open our eyes in time to see it, if it were necessary for us to open them at all.  But whether our eyes be open or shut, it makes no difference whatever; for when our Lord wills, we must see it, whether we will or not.  No distraction can shut it out, no power can resist it, nor can we attain to it by any diligence or efforts of our own.  –The Life of St Teresa of Avila