“The Church’s social teaching argues on the basis of reason and natural law, namely, on the basis of what is in accord with the nature of every human being. It recognizes that it is not the Church’s responsibility to make this teaching prevail in political life. Rather, the Church wishes to help form consciences in political life and to stimulate greater insight into the authentic requirements of justice as well as greater readiness to act accordingly, even when this might involve conflict with situations of personal interest. Building a just social and civil order, wherein each person receives what is his or her due, is an essential task which every generation must take up anew. As a political task, this cannot be the Church’s immediate responsibility. Yet, since it is also a most important human responsibility, the Church is duty-bound to offer, through the purification of reason and through ethical formation, her own specific contribution towards understanding the requirements of justice and achieving them politically.
The Church cannot and must not take upon herself the political battle to bring about the most just society possible. She cannot and must not replace the State. Yet at the same time she cannot and must not remain on the sidelines in the fight for justice. She has to play her part through rational argument and she has to reawaken the spiritual energy without which justice, which always demands sacrifice, cannot prevail and prosper. A just society must be the achievement of politics, not of the Church. Yet the promotion of justice through efforts to bring about openness of mind and will to the demands of the common good is something which concerns the Church deeply.”
Pope Benedict, Deus Caritas Est, 28