Tractates on the Gospel of John

^19. But perhaps the slow hearts of some of you cannot yet receive that light, because they are burdened by their sins, so that they cannot see. Let them not on that account think that the light is in any way absent, because they are not able to see it; for they themselves are darkness on account of their sins. “And the light shines in darkness, and the darkness comprehended it not.” Accordingly, brethren, as in the case of a blind man placed in the sun, the sun is present to him, but he is absent from the sun. So every foolish man, every unjust man, every irreligious man, is blind in heart. Wisdom is present; but it is present to a blind man, and is absent from his eyes; not because it is absent from him, but because he is absent from it. What then is he to do? Let him become pure, that he may be able to see God. Just as if a man could not see because his eyes were dirty and sore with dust, rheum, or smoke, the physician would say to him: “Cleanse from your eye whatever bad thing is in it, so that you may be able to see the light of your eyes.” Dust, rheum, and smoke are sins and iniquities: remove then all these things, and you will see the wisdom that is present; for God is that wisdom, and it has been said, “Blessed are the pure in heart; for they shall see God.”