O crystal well! Oh that on Thy silvered surface Thou wouldest mirror forth at once Those eyes desired Which are outlined in my heart! ~ 12 - John of the Cross

But it may be asked: Why does the soul call the divine light, which enlightens the soul and purges it of its ignorances, the dark night? I reply, that the divine wisdom is, for two reasons, not night and darkness only, but pain and torment also to the soul. The first is, the divine wisdom is so high that it transcends the capacity of the soul, and therefore is, in that respect, darkness. The second reason is based on the meanness and impurity of the soul, and in that respect the divine wisdom is painful to it, afflictive and dark also.

In search of my Love I will go over mountains and strands; I will gather no flowers, I will fear no wild beasts; And pass by the mighty and the frontiers. ~ 3

Hence, for the soul to be in its center - which is God, as we have said - it is sufficient for it to possess one degree of love, for by one degree alone it is united with him through grace. Should it have two degrees, it becomes united and concentrated in God in another, deeper center. Should it reach three, it centers itself in a third. But once it has attained the final degree, God's love has arrived at wounding the soul in its ultimate and deepest center, which is to illuminate and transform it in its whole being, power, and strength, and according to its capacity, until it appears to be God. When light shines on a clean and pure crystal, we find that the more intense the degree of light, the more light the crystal has concentrated within it and the brighter it becomes; it can become so brilliant from the abundance of light received that it seems to be all light. And then the crystal is undistinguishable from the light, since it is illumined according to its full capacity, which is to appear to be light.