Augustine added to his solution that free will was the cause of our ill doings as we turn aside from God to a lesser good. God has given us free will, which allows us to act morally, and thus decide whether to be good, as God intended by which can do in following His commandments, or we can choose to turn away from those greater goods. Augustine believed that if God had programmed us to always choose good over evil we wouldn’t do any harm, but we then would not really be free. Augustine argued that it is better that God had given us a choice to decide whether to be of a higher good or of a much less sense of good, that being something evil. Otherwise, we would be God’s puppets, under His control so that we may always behave ourselves and stray from violence and other evils. To Augustine, God is powerful enough to prevent evil, but the fact that evil still exists is not directly due to God in his conclusion. More so that moral evil is a result of our choices made, and to Augustine, was a result of the choices Adam and Eve made in the Garden of Eden. Augustine’s theory of God as an all-present being who could end evil but allows it to happen due to his creation’s (people’s) ability to have free will to remain convinces many believers to believe in an all-knowing, all-powerful, and al-good God since we (people) are the true source of evil through decisions made through free will.
https://www.str.org/articles/augustine-on-evil#.WO-TtG8rLcs & Ch. 6 of L.H.