Faith has a great place in the epistemology of Augustine, who adopted the phrase “you will not understand unless you believe (_nisi credideritis, non intellegetis_).” This situation has led to the comments by the philosophers that reason is insufficient or has no importance in Augustine, but according to Augustine, reaching the truth is only possible with the working of reason and belief together, and it cannot happen without any of them. The rational part of the soul (_animus_), which is at (...) the top of it, is like a door to God, but faith is essential for this to be possible. According to Augustine, the reason why faith is necessary for the realization of divine illumination, which is the only way to reach the truth, is that the will, polluted by original sin, hinders the mind, and that which will enable the mind to grasp all mysteries is the purification of the will by faith. In this study, why Augustine used faith together with reason will be examined in terms of the relationship between divine illumination and the will. (shrink)