What effects does prayer bring about in the soul?
Prayer produces a certain conversion of the heart towards him who is already ready to give inasmuch as we are in condition to receive. And in this conversion a purification of the interior eye is wrought in such a way that those things in the temporal order which we used to desire are excluded. In this way the inner eye, having become pure, can withstand the pure light… but not only withstanding the light, it dwells in it too.
from St. Augustine Answers 101 Questions on Prayer by Fr. Ermatinger.
Prayer brings about two changes in the soul, both by God’s grace. A soul that is diligent in her prayers is a soul that is turning away from the allure of the things of this world and increasingly seeks after God and His good things. The soul detaching from the things of this world experiences an increased longing for God and a dissatisfaction with worldly things, while it may be with fervor and zeal, brings peace and stability to the soul. While the seeking after created goods is a seeking for things that once obtained cannot truly satisfy nor satiate, owing to the transitory nature of created goods and man’s enteral end, seeking after God and His good things brings hope backed by faith in God’s promises to give His good things to those who turn to Him in prayer. This hope brings clarity, for its increase is also the increase of faith by which one knows more certainly of God and His good things. If one knows by faith more clearly, one hopes more surely and can more readily weather the storms of this world because one’s hopes are placed in the omnipotent God.
This purification of man’s actions and inner self begins with and is completed by the gift of God’s grace that man cooperates with by the turn of prayer. Through grace, God gives charity, which not only repairs and reconfigures the human soul, making it ready and capable of receiving her God and Bridegroom, but it is through which God comes to dwell with and in her. Charity is preparing the soul not to just hear of God, but to see Him directly. The created soul doesn’t have the ability to see God, that is to know Him directly without mediation. God must not only speak, give mediated revelation about Himself (faith), but also bring about the ability for the soul to see. How can one see God? Created things cannot do this, only God can see Himself as He is, only True Light can gaze upon True Light, see and know directly. It can only be, then, that God is that by which the soul shall see God face to face, or more precisely, by the grace of Charity that dwells within the human soul. In prayer, God gives the soul a new heart by which to see Him, a living heart, His heart.
The soul’s inner eye, its heart, its inner chamber, the Chamber of the Bridegroom becomes purified and becomes capable of having God present through the working of prayer. What once was in darkness and blinded by the Divine Light which it could not see begins to see, begins to know, begins to love God. As Charity dwells within the soul, the soul dwells with Him who created her, for Him whom she longs, and begins to enjoy Him in who is her fulfillment.