The second volume of The Knowledge of God pursues a much more linear historical approach in comparison to the previous volume. While continuing its thematic focus on revelation, it bears the mark of a historian in its profuse use of historical examples. Beginning with the Old Testament, Gwatkin argues that the Jewish religious tradition took a step beyond what Greek philosophers or their contemporaries had done by promoting the unity of God in a world of polytheism and not allowing God to be debased with human corruptions. The framing of Old Testament laws put sin into its rightful place, whereas Greek asceticism had merely attributed it to human nature. For Gwatkin, the compilers of the New Testament place Christ in his rightful place as the fulfilment of all previous revelation: ‘This, in fact, is the distinctive doctrine of Christianity—that the revelation in Christ’s Person sums up all the rest. Islam and Pharisaism sum up revelation in a book, Christianity in a Person’. Revelation is manifest in life not in knowledge. As a result, for the early church, knowledge of Christ was knowledge of God. He goes on to explain the systemization of the reality of Christ’s revelation in the writings of the early church by Clement, Clement, Philo, Athanasius and others, and ultimately the need to define the doctrine of Christ’s incarnation at the Council of Nicea. For Gwatkin, the Council of Nicea ‘not only saved Christianity’ by defending Christ as the ultimate revelation of God entering into the world in the incarnation, but ‘the political freedom of the distant future’ by preventing Christianity from slipping back into paganism or shaping itself on ‘despotic ideals’. Moving from the need to define Christ and the controversies which sprang out of a desire to apply human reason in defining the incarnation, the final portion of Gwatkin’s discussion of the ‘Nicene Age’ in Lecture 16 focuses on the Muslim conception of God. He compares the difficulties faced in Christianity’s gradual doctrinal formation with the rigidness of Islam and its refusal to allow reason a place in theological formation, which, although it provides a solid framework preventing controversy, ‘allows no growth’. Returning to Rome, the author describes the growth of Mithraism as a point of transition in the Roman world from polytheism to a ‘higher concept of revelation’.

The middle section of the second volume charts the transformation of the church’s role from interpreting revelation and defining doctrine to being the sole provider of the means of grace. Lecture 18 argues the formulation of a doctrine of infallibility in the church, as formulated in the works of Cyprian, rests on a demand by the laity for a clear yard marker of the revelation necessary for salvation. In so doing, a doctrine took root that the church represents the only conduit of true revelation. Augustine, in the face of persecution and the Manichean, Donatist and Pelagian heresies, affirmed the role of the church in revelation, although Gwatkin makes a distinction between the church being a ‘necessary sphere of that experience’ (revelation) and any claim that Augustine believed the church was a ‘necessary mediator’. Gradually, however, the doctrine of the church shifted from the church being the sole dispenser of revelation and mediation to the church being the sole dispenser of the means of grace. Entry into the church came through baptism, without which salvation could not be attained. As a result, the church grew in power and influence. Gwatkin traces the rise of the medieval church, its growing corruption and the monastic and mystical strands that developed in response, which sought the knowledge of God in the individual experience as opposed to the corporate. Sticking to the theme of revelation, he states that these individuals seeking personal revelation, along with Pascal and the Jansenists in the seventeenth century, went against the church’s continued doctrinal position that revelation comes through the church alone as it was again ascribed by the Council of Trent.

It is in his treatment of Roman Catholicism that Gwatkin’s lecture deviates from its historical pattern. He slips into a diatribe and is damning on all counts. In the closing lines of Lecture 20, he declares revolution is the only way forward for the Roman Catholic Church: ‘meaner churches may repent and amend; but for Rome reform is suicide’.

The author’s treatment of the Reformation movements is succinct, comparing the continental reformations in the Swiss cantons and Germany with the Reformation in England. Again, Gwatkin maintains that the ‘first principle’ driving the Reformation was a ‘belief that the knowledge of God is direct and personal’. That is to say, the pursuit of revelation laid the foundation and, as such, the Reformers set to ‘clearing away doctrines and institutions’ which detracted from this aim. In this process, Gwatkin argues, the Reformers remodelled the whole concept of revelation. They replaced the infallible church with the infallible Bible. Where Rome had taken away revelation from the people in exchange for membership in an infallible church and certain salvation, the Protestant answer, according to the author, removed ethics and replaced them with dogma. Ultimately, this belief justified Protestant involvement in the Thirty Years’ War.

In addressing the progression of thought beyond the Reformation, Gwatkin addresses several aspects of contemporary thought looking both back at the past and on toward the future. He argues that science has brought much to bear on the study of religion by way of clearing away misconceptions. First, Gwatkin claims science has established that the natural world is planned and suggests ‘one plan, one Power behind it, and no more’. Second, science has dispelled the belief that if God is to act in the world, it must be from outside. Third, science has dispelled Aquinas’ distinction between a kingdom of nature and a kingdom of grace which are ruled by different laws. With respect to Scripture, biblical criticism has stripped away much of the vestiges of it being the infallible word of God, but not the power within the gospel. It remains ‘the substance of revelation, namely, that God has given us a final assurance of his goodness and certain alleged historical facts of the life of Jesus Christ’. The power of Christian revelation, he argues, reaches beyond religion and has been manifested in social and political movements and in a higher sense of social duty. Revelation and Christian practice must not be utterly detached from society and culture.