33 In the life of Saint Augustine we find a significant example of this process whereby reason, with its desire for truth and clarity, was integrated into the horizon of faith and thus gained new understanding. Augustine accepted the Greek philosophy of light, with its insistence on the importance of sight. His encounter with Neoplatonism introduced him to the paradigm of the light which, descending from on high to illumine all reality, is a symbol of God. Augustine thus came to appreciate God’s transcendence and discovered that all things have a certain transparency, that they can reflect God’s goodness. This realization liberated him from his earlier Manichaeism, which had led him to think that good and evil were in constant conflict, confused and intertwined. The realization that God is light provided Augustine with a new direction in life and enabled him to acknowledge his sinfulness and to turn towards the good. All the same, the decisive moment in Augustine’s journey of faith, as he tells us in the Confessions , was not in the vision of a God above and beyond this world, but in an experience of hearing. In the garden, he heard a voice telling him: "Take and read". He then took up the book containing the epistles of Saint Paul and started to read the thirteenth chapter of the Letter to the Romans. In this way, the personal God of the Bible appeared to him: a God who is able to speak to us, to come down to dwell in our midst and to accompany our journey through history, making himself known in the time of hearing and response. Yet this encounter with the God who speaks did not lead Augustine to reject light and seeing. He integrated the two perspectives of hearing and seeing, constantly guided by the revelation of God’s love in Jesus. Thus Augustine developed a philosophy of light capable of embracing both the reciprocity proper to the word and the freedom born of looking to the light. Just as the word calls for a free response, so the light finds a response in the image which reflects it. Augustine can therefore associate hearing and seeing, and speak of "the word which shines forth within". The light becomes, so to speak, the light of a word, because it is the light of a personal countenance, a light which, even as it enlightens us, calls us and seeks to be reflected on our faces and to shine from within us. Yet our longing for the vision of the whole, and not merely of fragments of history, remains and will be fulfilled in the end, when, as Augustine says, we will see and we will love. Not because we will be able to possess all the light, which will always be inexhaustible, but because we will enter wholly into that light.
Source: Lumen Fidei (Vatican.va)