Argument's for and against St. Augustine's explanation of evil in the world?

This argument doesn't make sense, because if God made free will, then he still created the potential for evil. I would say that he had to make evil for there to be a good. There had to be choices to be free will. Did you know that traditionally in the Old testament, Satan was not an enemy of God, but God's servant? Which explains the book of Job. Somewhere in the New Testament time we started referring to Satan as the enemy, but we are only assuming God has not placed him there to tempt us.