The Social Gospel is a perspective on American Christianity that has its origins in the late 1800s, following the commencement of the industrial revolution. Not long thereafter, corporate structures emerged that became more powerful, which of course led to many labour strikes and led many to consider Socialism as a viable alternative to laissez-faire economics.
As labor strikes became more prevalent, the long-held "protestant work ethic" became a less viable worldview to hold, as churches began to see the social problems that unrestrained Capitalism was unearthing, particularly amongst labourers.
Meanwhile, as the study of both social science and socialism were increasing in institutes of higher learning, and the church stayed no stranger to this. Seminaries undertook studies of both, as efforts to try and alleviate some of the stresses placed on society.
Further down the road, and taken out of a secular context, some aspects of socialism (specifically, the good of society, as opposed to individualistic gain) became an important plank in the concept known as the Kingdom of God, where salvation and well-being of society as a whole was deemed more important than that of the individual, and provided a vehicle for Christians to perform ethically for the good of all, as opposed to doing something simply for their own good. The Kingdom of God does not try to overthrow existing precepts of Christianity, or throw out existing church doctrines. Instead, it attempts to redefine the focus of the faith on social change as opposed to individual salvation.
Growing out of this movement was the Social Gospel. Just as the Kingdom of God does not attempt to change long-standing Christian precepts, the Social Gospel (or "Social Christianity") does not aim to overthrow capitalism, but instead focuses on reforming society and capitalism from the inside, as opposed to revolution from the outside.
One prominent theologian in particular come to mind when considering the Kingdom of God and the Social Gospel, Walter Rauschenbusch, whose seminal work, A Theology for the Social Gospel, outlines the necessity to focus on the social conciousness within the existing Christian doctrines -- in fact, some might argue that he makes social change the main focus of salvation itself. Rauschenbusch argues that complete salvation, "...would consist in an attitude of love in which he would freely co-ordinate his life with the life of his fellows in obedience to the loving impulses of God..."1 Thus, regarding personal salvation, "When we submit to God, we submit to the supremacy of the common good"2 and "A religious experience is not Christian unless it binds us closer to men and commits us more deeply to the Kingdom of God."3
Another theologian whose contributions needn't go unnoticed is Reinhold Niebuhr, whose time spent at a working-class Detroit church, and whose book Moral Man and Immoral Society both had a great focus on societal change, although Neibuhr recognised that all groups -- including the church -- featured imperfections and tendencies towards excess.
Works Referenced:
* Matthews, Terry: The Social Gospel
(http://www.wfu.edu/~matthetl/perspectives/nineteen.html)
* Placher, William C.: A History of Christian Theology
* Rauschenbusch, Walter: A Theology For the Social Gospel
Works Cited:
1 p. 98, A Theology For the Social Gospel: Walter Rauschenbusch, (c) 1945. Abingdon Press: New York, New York.
2 ibid., p. 99
3 ibid., p. 105