It is an extraordinarily impressive fact that that greatest of theological giants St Paul, whose thoughts range through the universe, embracing in their width and scope and penetration the mysteries of life and death, things present and things to come, stands firmly based on 'the simplicity that is in Christ' (II Cor. 11.3). It is indeed this 'single-hearted devotion to Christ' (as the New English Bible translates it) that underlies both his profound insight into the divine wisdom and his revolutionary understanding of human existence.
Of Paul's greatest twentieth-century exponent, Karl Barth, the same could be said. His productivity has been immense, his horizons all-embracing, his domination of the contemporary theological scene unquestioned. Probably not since Calvin has there appeared a figure of like dimensions; and even those whose interpretation of the faith at many points is radically different have gladly confessed their indebtedness. Distinguished Roman Catholic theologians have listened attentively to this trumpet-toned Protestant voice, and have acknowledged the validity of this consuming quest of the truth. Yet the fact remains that this Colossus of a theologian is basically concerned with simple things; and no one reading Barth can have any doubt that the driving force behind the mighty argument is the man's own single-hearted devotion to Christ. This is what makes the encounter with Barth, even through the printed page, a spiritual experience.