“I think that here a great sacrament is commended, because every soul, as long as it is in sin, is in a kind of darkness and confusion. But it can not emerge from its confusion and be disposed to the order and form of justice, unless it be first illumined to see its evils, and to distinguish light from darkness, that is, virtues from vices, so that it may dispose itself to order and conform to truth. Thus, therefore, a soul lying in confusion can not do without light, and on this account it is necessary first that light be made, that the soul may see itself, and recognize the horror and shamefulness of its confusion, and extricate itself, and fit itself to that rational disposition and order of truth. Now, after all relating to it has been put in order and has been disposed according to the exemplar of reason and the form of wisdom, then straightway will the sun of justice begin to shine for it, because thus it has been said in promise: “Blessed are the clean of heart: for they shall see God” (Matt. 5, 8). First, therefore, light is created in that rational world of the human heart, and its confusion is illumined that it may be reduced to order. After this, when the interior of this confusion has been purified, the clear light of the sun comes and illuminates it. For it is not worthy to contemplate the light of eternity, until it has become clean and purified, having, as it were, beauty through matter and disposition through justice.”
¬ Hugh of St. Victor, De Sacramentis, Bk. One, Chapter XII.