This article probes into Karl Barth's treatment of the concepts of original sin and the bondage of the will in §60 and §65 of Church Dogmatics IV/1-2. He redefines human nature as a total determination of the human being (Sein/Dasein) "from above" by the covenantal history of reconciliation, which remains totally intact in the state of sin. The human being, however, is also determined "from below" by the Adamic world-history of total corruption. With this actualistic construal of sin and human nature, Barth redefines original sin as the radically sinful activities and decisions that determine the confinement of human beings to the historical condition of fallenness. Along the same line he uses the present active indicative to express his actualistic reorientation of the Augustinian notion of the bondage of the will: "non potest non peccare". This article concludes by considering some substantive and methodological implications of this formulation of sin and human nature for Sino-Christian theology.