According to Pope Benedict XVI, its purpose "is simply to help purify reason and to contribute, here and now, to the acknowledgment and attainment of what is just…. [The Church] has to play her part through rational argument and she has to reawaken the spiritual energy without which justice…cannot prevail and prosper", According to Pope John Paul II, its foundation "rests on the threefold cornerstone of human dignity, solidarity and subsidiarity". These concerns echo elements of Jewish law and the prophetic books of the Old Testament, and recall the teachings of Jesus Christ recorded in the New Testament, such as his declaration that "whatever you have done for one of these least brothers of Mine, you have done for Me."
Catholic social teaching is distinctive in its consistent critiques of modern social and political ideologies both of the left and of the right: liberalism,communism, feminism, atheism, socialism, fascism, capitalism, and Nazism have all been condemned, at least in their pure forms, by several popes since the late nineteenth century.
Quadragesimo Anno
: Encyclical of Pope Pius XI, on the Reconstruction of the Social Order, May 15, 1931
In the midst of the great depression, in the age of dictators and ruthless totalitarian systems of the right and the left, Pope Pius XI celebrates the fortieth anniversary of Rerum Novarum. He reaffirms the principles set out by Leo XIII and applies them to the current