Helmut Richard Niebuhr (/ˈniːbʊər/; September 3, 1894 – July 5, 1962) was an American theologian and Protestant minister who is considered one of the most important Christian ethicists in 20th-century America.
Both brothers were, in their day, important figures in the neo-orthodox theological school within American Protestantism.
While living in St. Louis, he was a member and leader in Evangelical United Church of Christ in Webster Groves, Missouri, and taught at Eden Theological Seminary from 1919 to 1924 and from 1927 to 1931.
Niebuhr was concerned throughout his life with the absolute sovereignty of God and the issue of historical relativism.
In this regard, Niebuhr held something of a middle ground between the dogmatic but dialectical theology of Karl Barth and the philosophically oriented modified liberalism of Paul Tillich.
Niebuhr's theology shows great sensitivity to how expressions of faith differ from one religious community to another.
His thought in some respects anticipated latter-day liberal Protestant concerns about pluralism and tolerance.
In this capacity, his biggest concern was how human beings relate to God, to each other, to their communities, and to the world.