6 And what is it that disorders the eye of the heart? Evil desire, covetousness, injustice, worldly concupiscence, these disorder, close, blind the eye of the heart. And yet when the eye of the body is out of order, how is the physician sought out, what an absence of all delay to open and cleanse it, that that may be healed whereby this outward light is seen! There is running to and fro, no one is still, no one loiters, if even the smallest straw fall into the eye. And God it must be allowed made the sun which we desire to see with sound eyes.
Much brighter assuredly is He who made it; nor is the light with which the eye of the mind is concerned of this kind at all. That light is eternal Wisdom. God made you, O man, after His own image. Would He give you wherewithal to see the sun which He made, and not give you wherewithal to see Him who made you, when He made you after His own image? He has given you this also; both has He given you. But much do you love these outward eyes, and much do you despise that interior eye; it you carry about bruised and wounded.
Yea, it would be a punishment to you, if your Maker should wish to manifest Himself unto you; it would be a punishment to your eye, before that it is cured and healed. For so Adam in paradise sinned, and hid himself from the face of God. As long then as he had the sound heart of a pure conscience, he rejoiced at the presence of God; when that eye was wounded by sin, he began to dread the Divine light, he fled back into the darkness, and the thick covert of the trees, flying from the truth, and anxious for the shade.
Source: Sermons on Selected Lessons of the New Testament (New Advent)