The author describes the purpose of his book in the following words: "The purpose of this work is to set out, as fairly as I can, Augustine's final understanding of divine predestination and his attempt to reconcile it with his continued assertion that free choice continues to exist in fallen human beings" (p. ix). As a well-known and respected Augustinian scholar, Gerald Bonner does a masterful job of shedding light on this paradox found in the writings and sermons of Augustine. He does this by examining the influences upon Augustine throughout his life as well as the theological controversies in which he was involved while pointing out that Augustine was not a systematic theologian but rather a rhetorician.
Recognizing the Manichean and Neo-Platonic influences on Augustine, Bonner also deals with the Pelagian heresy, noting, however, that Augustine's doctrines were in place long before he entered into the Pelagian controversy. Bonner points out that the difference between Pelagius and Augustine lies essentially in their understanding of the nature of the Fall of Adam. Their major difference is to be found in their understanding of human free will. For Pelagius, free will is still with humans after the Fall. Following what was to become known as the biological transmission theory of Original Sin, Augustine taught that the capacity for free will was lost for all humankind because of Adam's sin, and God's grace is necessary to do good. This grace comes with baptism and without baptism, after death, one is condemned to hell. Only unbaptized martyrs are exempted. Bonner quotes from Augustine that: "...no one is made a member of Christ, except either by baptism in Christ or by death for Christ" (p. 15). From this belief was formulated his pessimistic doctrine of divine predestination with Augustine holding that the majority of humankind is destined for damnation. Only a small proportion of humanity has been selected by God for salvation. Not all are saved; only those who respond to God's special grace received through baptism. "The essence of Augustine's predestinarian theology was the conviction of the omnipotence of God, Who has created all things from nothing" (p. 5). For Augustine, the Pelagian view of Adam's sin led to the sin of human pride, since "Pelagius denied the existence of any transmission of Adam's guilt" (p. 67). But Pelagianism did emphasize the responsibility of the individual for his actions in the eyes of God.
The major paradox running through Augustine's theology is to be found in his pessimistic and very harsh doctrine of divine predestination and the fact that he also wrote and preached widely about God being not only a God of justice but a God of mercy as well, who has loved humans before the foundation of the world. In the end, Bonner speculates that Augustine seemed to be too busy in theological controversy during his lifetime to construct a single, comprehensive and coherent system of theology. While dealing with the Pelagian controversy, Bonner does somewhat rehabilitate Pelagius, especially in light of the more contemporary understanding of Original Sin. As a matter of fact, he delineates the merits and the demerits of both Pelagianism and Augustinianism, finding fault with both of them. Arguing that the writings of St. Paul had a very large influence upon Augustine, Bonner also admits that the traditional teaching of the church as well as the established and popular beliefs of the Christians of his day were very influential. Bonner throughout supplies adequate references from original sources to verify his assertions as well as providing a select bibliography at the end of his work. His book will prove very helpful not only to the person already engaged in the study of Augustinian theology but also the initiate as well.