An extract from 'The Dark Night of the Soul by St. John of the Cross'
† Download the book   (download instuctions)
Hence it follows that, the nearer to God are the higher spirits and the lower, the more completely are they purged and enlightened with more general purification; and that the lowest of them will receive this illumination very much less powerfully and more remotely.
Hence it follows that man, who is the lowest of all those to whom this loving contemplation flows down continually from God, will, when God desires to give it him, receive it perforce after his own manner in a very limited way and with great pain.
For, when the light of God illumines an angel, it enlightens him and enkindles him in love, since, being pure spirit, he is prepared for that infusion. But, when it illumines man, who is impure and weak, it illumines him, as has been said above, according to his nature.
It plunges him into darkness and causes him affliction and distress, as does the sun to the eye that is weak; it enkindles him with passionate yet afflictive love, until he be spiritualized and refined by this same fire of love; and it purifies him until he can receive with sweetness the union of this loving infusion after the manner of the angels, being now purged, as by the help of the Lord we shall explain later.
But meanwhile he receives this contemplation and loving knowledge in the constraint and yearning of love of which we are here speaking.