The Ascent of Mount Carmel: Book Two, Chapter 6
The theological virtues perfect the faculties of the soul and produce emptiness and darkness in them.
Excerpts concerning the virtue of hope
We must discuss the method of leading the three faculties (intellect, memory, and will) into this spiritual night, the means to divine union. But we must first explain how the theological virtues, faith, hope, and charity (related to these faculties as their proper supernatural objects), through which the soul is united with God, cause the same emptiness and darkness in their respective faculties: faith in the intellect, hope in the memory, and charity in the will. Then we shall explain how in order to journey to God the intellect must be perfected in the darkness of faith, the memory in the emptiness of hope, and the will in the nakedness and absence of every affection.
As a result it will be seen how necessary it is for the soul, if it is to walk securely, to journey through this dark night with the support of these three virtues. They darken and empty it of all things. As we said, the soul is not united with God in this life through understanding, or through enjoyment, or through imagination, or through any other sense; but only faith, hope, and charity (according to the intellect, memory, and will) can unite the soul with God in this life.
These virtues, as we said, void the faculties: Faith causes darkness and a void of understanding in the intellect, hope begets an emptiness of possessions in the memory, and charity produces the nakedness and emptiness of affection and joy in all that is not God.
Hope, also, undoubtedly puts the memory in darkness and emptiness as regards all earthly and heavenly objects. Hope always pertains to the unpossessed object. If something were possessed there could no longer be hope for it. St. Paul says ad Romanos: Spes quae videtur, non est spes; nam quod videt quis, quid sperat? (Hope that is seen is not hope. For who hopes for what he sees?) [Rom 8:24]. As a result this virtue also occasions emptiness, since it is concerned with unpossessed things and not with the possessed object.
In the sixth chapter of Isaiah we read that the prophet saw a seraph at each side of God, and that they each had six wings: with two wings they covered their feet, which signified the blinding and quenching of the affections of the will for God; with two they covered their faces, which signified the darkness of the intellect in God’s presence; and with the two remaining wings they flew, so as to indicate the flight of hope toward things that are not possessed, an elevation above everything outside of God that can be possessed, earthly or heavenly [Is. 6:2].
Saint John of the Cross
John of the Cross, St. 1991, The Collected Works of St. John of the Cross, Revised Edition, translated from the Spanish by Kavanaugh, K and Rodriguez, O with revisions and introductions by Kavanaugh, K, ICS Publications, Washington DC.