When the soul is plunged in the fire of divine love, like iron, it first loses its blackness, and then growing to white heat it becomes like unto the fire itself. And lastly, it grows liquid, and, losing its nature, is transmuted into an utterly different quality of being.
And as the difference between iron that is cold and iron that is hot, so is the difference between soul and soul, between the tepid soul and the soul made incandescent by divine love. Richard of St. Victor
Richard of Saint Victor, (died 1173) is known today as one of the most influential religious thinkers of his time. He was a prominent mystical theologian, and was prior of the famous Augustinian Abbey of Saint Victor in Paris from 1162 until his death in 1173.