If you say, “Show me your God,” I will say to you, “Show me what kind of person you are, and I will show you my God.” Show me then whether the eyes of your mind can see, and the ears of your heart hear. It is like this. Those who can see with the eyes of their bodies are aware of what is happening in this life on earth. They get to know things that are different from each other. They distinguish light and darkness, black and white, ugliness and beauty, elegance and inelegance, proportion and lack of proportion, excess and defect. The same is true of the sounds we hear: high or low or pleasant. So it is with the ears of our heart and the eyes of our mind in their capacity to hear or see God. God is seen by those who have the capacity to see him, provided that they keep the eyes of their mind open. All have eyes, but some have eyes that are shrouded in darkness, unable to see the light of the sun. Because the blind cannot see it, it does not follow that the sun does not shine. The blind must trace the cause back to themselves and their eyes. In the same way, you have eyes in your mind that are shrouded in darkness because of your sins and evil deeds. A person’s soul should be clean, like a mirror reflecting light. If there is rust on the mirror his face cannot be seen in it. In the same way, no one who has sin within him can see God.
From the book addressed to Autolycus by Saint Theophilus of Antioch, bishop