Abstract: Despite their radically different orientations, Confucianism and Christianity have a point of convergence central to their interpretations, i.e., “how to be fully human.” This focal point has produced distinctive but comparable doctrines, the Confucian teaching of self-cultivation and the Christian doctrine of sanctification. Hence, the thesis is that, in the light of paradigmatic teachings of Wang Yang-ming and Karl Barth, self-cultivation and sanctification are thickly resemblant views of a common issue, i.e., radical humanization. First, Wang and Barth made crucial paradigm changes for two converging goals: restating a unified foundation of faith and opening the dynamic possibility of human involvement. Taking one’s commitment as the point of departure rather than a metaphysics or a philosophy of religion, both assert the unity of ontological knowledge and ethical practice. Secondly, Wang and Barth articulate the task in a similar structure. Establishing the root-paradigm of radical humanity (liang-chih, humanitas Christi) as the ontological reality, both define humanization as a process of realizing this transcendent reality beyond the ambiguous existential situation. Both believe that root paradigm gives concrete direction (Tao, Weisung) through the spiritual empowerment, fully revealing evil which has arisen by a dysfunction of the ontological reality. Thirdly, Wang and Barth present the same material definition of humanity (jen, imago Dei); namely, co-humanity or Mitmenschlichkeit. Understanding selfhood as a center of relationship, both advocate the concrete-universal way of its realization in an ever-expanding circle of human relatedness. These thick resemblances may have provided a basis for the success of the Korean Presbyterian mission. Hence, this dissertation suggests the following: the study of Confucianism as constitutive of doing East Asian theology; a task of East Asian theology as an a posteriori thematization for the communities of faith in the historic encounter; an appropriate scrutiny on the fusion of these two traditions by the relation of theology and confuciology, as thick-descriptive explications of each tradition; and a new paradigm of Christology, i.e., Confucian (Sage) Christology, which may overcome the problems of traditional Christologies with profound Confucian insights.