This thesis in Church History presents a biographic study on the life of Ben Marais against the political and ecclesiastic background of South Africa of the 20th century. The significance of Ben Marais’ life is approached through his correspondence with the secretaries of the World Council of Churches during the 1960s and 1970s. The letters, pertaining to the World Council of Churches financial and moral support for the organisations fighting against Apartheid, reflect on Ben Marais’ involvement with the World Council and his particular concerns. Through a study on the life of Ben Marais insight can be gained into the thinking of the leadership of the NG Kerk. The study presents Ben Marais as a prophet who challenged the then popular tendencies in the NG Kerk theology on policy justification and on the relation between religion and nationalism. The central question in this study asks, what led an ordinary man, of humble background, to the insights he reflected, and guided him through times of transparent opposition to maintain his belief in what was right and just? What was the essence of his theology and understanding of the South African problem? To what extent could the church leaders of the present, and the future learn from his example and life, in terms of the tribulations faced, different schools of thought, and sentiments, both nationalistic and spiritual? The study then wishes to test the following hypothesis: Ben Marais can be considered as one of the steadfast and humble prophets of the church in Southern Africa during the 20th century, who serves as an example of Christian Brotherhood, regardless of the perplexities, for present and future generations on relations between the affairs of faith, state and society. The thesis presents a broader introduction on Church Historiography. Ben Marais’ own historiographical reflection is considered. The approaches to history are summarised as background to the periodisation model adopted by the study. The study wishes to work with a thematic model set against a chronological framework. Sensitivity to geographical concerns is also expressed. Afrikaner Nationalism is not seen in isolation, but in relation to African, English and Indian Nationalism.