The relation between evil and will in human actions in Augustine's Thought

Augustine believes that there are some evils in the world so that no one can deny it .But, he encounters with difficulty in explaining evil in the world. He, on one hand, denies the Manichean belief in duality and on the other, believes that God is the supreme good (summum bonum) and cannot be the creator of evil. Augustine provides some solutions to this problem including of which is that the free will of man in the world is the source of any evil. In the article, the main issue is that the human free-will is not free after the Fall because we are received the original sin from our preceding generations. Augustine believes that the will is only and only free if it is blessed by the divine grace mediator of which is Jesus. The authors try to answer these questions: How does Augustine solves the contradiction between God, the Omnipotent, the Supreme Good, and the evil in the world? How can human beings do evils when they have not free will after the Fall? Does Jesus as the mediator of grace, possess free-will and which wills are enjoyed from the divine grace? According to the fact that the will is the source of evil and that it had not been created but by God, Is not God the creator of evil in the world? In his philosophy, Augustine answers these questions with the aid of Christian dogma, since in his thought, faith is superior to reason.