From “Oration 6, On the Beatitudes” (ca. 375)
“Blessed are the pure in heart, for they shall see God.” I do not think that if the eye of one’s soul has been purified, one is promised a direct vision of God; but perhaps this marvelous saying may suggest what the Word expresses more clearly when he says to others: “The kingdom of God is within you.” By this we should learn that if one’s heart has been purified from every creature and all unruly affections, one will see the Image of the Divine Nature in one’s own beauty.
I think that in this short saying the Word expresses some such counsel as this: There is in you, human beings, a desire to contemplate the true good. But when you hear that the Divine Majesty is exalted above the heavens, that its glory is inexpressible, its beauty ineffable, and its nature inaccessible, do not despair of ever beholding what you desire. It is indeed within your reach; you have within yourselves the standard by which to apprehend the Divine. For he who made you did at the same time endow your nature with this wonderful quality. For God imprinted on it the likeness of the glories of his own nature, as if molding the form of a carving into wax.
But the evil that has been poured all around the nature bearing the Divine Image has been rendered useless to you this wonderful thing, that lies hidden under vile coverings. If, therefore, you wash off by a good life the filth that has been stuck on your heart like plaster, the Divine Beauty will again shine forth in you.
To give an example. Though people who see the sun in a mirror do not gaze at the sky itself, yet they see the sun in the reflection of the mirror no less than those who look at its very orb. So, he says, it is also with you. Even though you are too weak to perceive the Light Itself, yet if you but return to the grace of the Image with which you were informed from the beginning, you will have all you seek in yourselves. For the Godhead is purity, freedom from passion, and separation from all evil. If therefore these things be in you, God is indeed in you.
Hence, if your thought is without any alloy of evil, free from passion, and alien from all stain, you are blessed because you are clear of sight. You are able to perceive what is invisible to those who are not purified because you have been cleansed; the darkness caused by material entanglements has been removed from the eyes of your soul, and so you see the blessed vision radiant in the pure heaven of your heart. But what is this vision? It is purity, sanctity, simplicity, and other such luminous reflections of the Divine Nature, in which God is contemplated.
St. Gregory of Nyssa (ca. 335-395) was a Cappadocian bishop and theologian, a defender of Nicene orthodoxy, famed for his integration of Platonism and the allegorical exegesis of Scripture. His feast is celebrated on January 10 and March 9 on the calendars of different churches.