You, O Lord, are our father;
our Redeemer from of old is your name.
Why, O Lord, do you make us stray from your ways
and harden our heart, so that we do not fear you?
Turn back for the sake of your servants,
for the sake of the tribes that are your heritage.
O that you would tear open the heavens and come down,
so that the mountains would quake at your presence—
to make your name known to your adversaries,
so that the nations might tremble at your presence!
When you did awesome deeds that we did not expect,
you came down, the mountains quaked at your presence.
From ages past no one has heard,
no ear has perceived,
no eye has seen any God besides you,
who works for those who wait for him.
You meet those who gladly do right,
those who remember you in your ways.
But you were angry, and we sinned;
because you hid yourself we transgressed.
We have all become like one who is unclean,
and all our righteous deeds are like a filthy cloth.
We all fade like a leaf,
and our iniquities, like the wind, take us away.
There is no one who calls on your name,
or attempts to take hold of you;
for you have hidden your face from us,
and have delivered us into the hand of our iniquity.
Yet, O Lord, you are our Father;
we are the clay, and you are our potter;
we are all the work of your hand.
Isaiah 63:16–17, 64:1–8
Since this transformation and union is something that does not fall within the reach of the senses and of human capability, the soul must perfectly and voluntarily empty itself — I mean in its affection and will — of all the earthly and heavenly things it can grasp. It must do this insofar as it can. As for God, who will stop him from accomplishing his desires in the soul that is resigned, annihilated, and despoiled?
But people must empty themselves of all, insofar as they can, so that however many supernatural communications they receive, they will continually live as though denuded of them and in darkness. Like the blind, they must lean on dark faith, accept it for their guide and light, and rest on nothing of what they understand, taste, feel, or imagine. All these perceptions are darkness that will lead them astray. Faith lies beyond all this understanding, taste, feeling, and imagining. If they do not blind themselves in these things and abide in total darkness, they will not reach what is greater: the teaching of faith.
Those who are not yet entirely blind will not allow a good guide to lead them. Still able to perceive a little, they think that the road they see is the best, for they are unable to see other and better ones. And because these individuals themselves are the ones giving the orders, they will consequently lead astray their young guide who has better vision. Similarly, if the soul in traveling this road leans on any elements of its own knowledge or of its experience or knowledge of God, it will easily go astray or be detained because it did not desire to abide in complete blindness, in the faith that is its guide. However impressive may be one’s knowledge or experience of God, that knowledge or experience will have no resemblance to God and amount to very little.
St. Paul also meant this in his assertion: Accedentem ad Deum oportet credere quod est (Whoever would approach union with God should believe in His existence) [Heb. 11:6]. This is like saying: Those who want to reach union with God should advance neither by understanding, nor by the support of their own experience, nor by feeling or imagination, but by belief in God’s being. For God’s being cannot be grasped by the intellect, appetite, imagination, or any other sense; nor can it be known in this life. The most that can be felt and tasted of God in this life is infinitely distant from God and the pure possession of him. Isaiah and St. Paul affirm: Nec oculus videt, nec auris audivit, nec in cor hominis ascendit quae praeparavit Deus iis qui diligunt illum (No eye has ever seen, nor ear heard, nor has the human heart or thought ever grasped what God has prepared for those who love him) [Is. 64:4; 1 Cor. 2:9].
Saint John of the Cross
The Ascent of Mount Carmel, II.4.2–4
New Revised Standard Version Bible: Catholic Edition scripture references provided by biblegateway.com
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.