Mater et Magistra §73

⁷³ In view of the rapid expansion of national economies, particularly since the war, there is one very important social principle to which We would draw your attention. It is this: Economic progress must be accompanied by a corresponding social progress, so that all classes of citizens can participate in the increased productivity. The utmost vigilance and effort is needed to ensure that social inequalities, so far from increasing, are reduced to a minimum.