"For the sake of further clarity in this matter, we ought to note that this purgative and loving knowledge, or divine light we are speaking of, has the same effect on a soul that fire has on a log of wood. The soul is purged and prepared for union with the divine light just as the wood is prepared for transformation into the fire. Fire, when applied to wood, first dehumidifies it, dispelling all moisture and making it give off any water it contains. Then it gradually turns the wood black, makes it dark and ugly, and even causes it to emit a bad odor By drying out the wood, the fire brings to light and expels all those ugly and dark accidents that are contrary to fire. Finally, by heating and enkindling it from without, the fire transforms the wood into itself and makes it beautiful as it is itself."

– The Dark Night, Book 2, Chapter 10