Catholic social teaching is the Catholic doctrines on matters of human dignity and common good in society. The ideas address oppression, social organization, concern for social justice, issues of wealth distribution, and the role of the state. Its foundations are widely considered to have been laid by Pope Leo XIII's 1891 encyclical letter Rerum novarum, which advocated economic distributism, criticized both capitalism and socialism, although its roots can be traced to the writings of Catholic thinkers such as Thomas Aquinas and Augustine of Hippo, and is also derived from concepts present in the Bible and the cultures of the ancient Near East.
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 cornerstones 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."