"Gregory of Narianzus says of this blessed vision that, "God can only be contemplated with a most subtle gaze of the spirit, and by a brief glance that takes place not in those things which are in God himself but in those things that surround him. In this way the face of truth is contemplated not from within truth itself but by means of those things that are close to truth. Before it can be held it flees, before it can be grasped it slips away. It offers itself to the heart, if the heart is pure, much as a stroke of flashing light illuminates human eyes by stunning them and then quickly passing away."
As another example of this blessed vision of God, we note that some cannot see this world's sun because it has not yet risen for them. In the same way, sinners dead in their sins cannot see nor sense the Sun of righteousness. These the Apostle rouses with the words: Awake, you sleeper! Arise from death, and Christ shall give you light (Eph 5:14). Some cannot see the sun because of a very opaque cloud that comes between their eyes and the sun. In the same way a spirit that has not been cleansed is completely obscured and clouded over by the fog of the world's everchanging variety and cannot see God until she is cleansed. Still others openly see the sun brightly shining, yet its brilliant rays pulse so powerfully into their weak eyes that they see that they are unable to see the ray's source. In this case it is not the absence of the sun but merely the eyes' weakness that incapacitates. One can indeed see the sun clearly without being blinded by its brilliance-if one is in open country early in the morning. That is how God is seen in heaven.
The more the cloud covering the sun thins out, the closer to the sun one's line of sight is. To this end the godly spirit, energetically wipes away the clouds of sins and bends her effort to cleansing-through repentance, mourning, confession, groans, asking pardon, yearning for grace and glory, bathing her couch with her tears, freeing herself for divine blessings through thirsting solicitude and varied longings, and busying herself in the practice of other virtues. Such holy pursuits seek out not only the flowers but also the roots of virtues as the godly spirit approaches the Sun of Righteousness. Just as a cloud covering the sun sometimes divides for an instant, permitting the sun to be seen everywhere, so sometimes (with God's help) the darkness and fog of the spirit that afflict every man in one degree or another dissolve or disintegrate, and the Sun of Righteousness, the true light who illumines every light in heaven and on earth, can be seen in a godly rapture of spirit.
Indeed, God, the Father of mercies and bestower of complete and holy consolation, who is kind and good to the soul who seeks him, often cracks open the cloud a bit for that seeking soul. Through these little cracks she can reach God's goodness through certain hidden aspirations of godly affections that penetrate her own cloud. In the process, she spiritually and sweetly tastes divine things without seeing them. This feeds and forms her in her infancy so that she might attain the aforementioned blessed vision and other divine things. With his face invisible, God assists the soul gazing in godly longing and moves and advances, attracts and restores her so that she delights in carrying out these daily exercises of a godly spirit. That is how a godly spirit thirsting for contemplation, knowledge, and love of her Creator, Redeemer, Ruler, and Savior gets started.
As the godly spirit perseveres, surrounded by roses and lilies of the valley, God teaches her how to ascend above to the rivers of waters, that is, to prepare her heart's ascents in the vale of tears and to seek through both speculative and anagogical contemplation. Ascending by clinging to God she is affected by thirst, and being thus affected, she clings to God all the more thirstily. For the Master of all things is the one who is enthroned in heaven and on earth and teaches men holy knowledge by means of the grace of godly affections and devotions, showing them what things are to be sought from God." pg. 207,208 Guigo De Ponte "On Contemplation"