Overview of the Twentieth Century
In 1900, the German church historian Adolph von Harnack gave a series of lectures that were later published as What Is Christianity? (1901). He argued that the kernel of the gospel is the commandment to love and the establishment of a just social order based on the universal fatherhood of God and the universal brotherhood of man. Harnack was following the lead of the German theologian Albrecht Ritschl, who had argued that ethics are the core of Christianity and called for a just and moral society that emulates Christ’s example and thus realizes the “kingdom of God.” This “social gospel” understanding of Christianity was advocated in the United States by the Baptist minister Walter Rauschenbusch, who critiqued laissez-faire capitalism as the culprit of the growing gap between rich and poor in America.