3 Today it is most important for people to understand and appreciate that the social question ties all men together, in every part of the world. John XXIII stated this clearly, (6) and Vatican II confirmed it in its Pastoral Constitution on The Church in the World of Today. (7) The seriousness and urgency of these teachings must be recognized without delay. The hungry nations of the world cry out to the peoples blessed with abundance. And the Church, cut to the quick by this cry, asks each and every man to hear his brother's plea and answer it lovingly.
Source: Populorum Progressio (Vatican.va)