Christians should cooperate, willingly and wholeheartedly, in building an international order based on genuine respect for legitimate freedom and on a brotherhood of universal friendship. This is all the more urgent because the greater part of the world still experiences such poverty that in the voices of the poor Christ himself can be heard, crying out for charity from his followers. There are nations — many of them with a majority of Christians — which enjoy an abundance of goods, while others are deprived of the necessities of life, and suffer from hunger, disease and all kinds of afflictions. This scandal must be removed from among men, for the glory of Christ’s Church and its testimony to the world are the spirit of poverty and the spirit of love.
Christians, especially young Christians, deserve praise and support when they offer themselves voluntarily in the service of other people, with bishops giving a lead by word and example, to do all in their power to relieve the sufferings of our times, following the age - old custom of the Church in giving not only what they can spare but also what they need for themselves.
Without being uniform or inflexible, a method of collecting and distributing contributions should be established in each diocese and nation and on a world-wide level. Whenever it seems appropriate, there should be joint action between Catholics and other Christians. The spirit of Charity, far from forbidding prudence and orderliness in social and charitable action, in fact demands them. Those intending to serve the developing countries must therefore undergo appropriate and systematic training.
In order to foster and encourage cooperation among men, the Church must be present and active in the community of nations. It must work through its own public organizations with the full and sincere cooperation of all Christians in their one desire to serve all mankind.
This end will be more effectively achieved if the faithful are themselves conscious of their human and Christian responsibilities and seek to awaken among those in their own walk of life a readiness to cooperate with the international community. Special care should be taken to give this kind of formation to young people in their religious and secular education.
Finally, it is to be hoped that, in carrying out their responsibilities in the international community, Catholics will seek to cooperate actively and constructively with other Christians, who profess the same Gospel of love, and with all men who hunger and thirst for true peace.
From the pastoral constitution on the Church in the modern world
of the Second Vatican Council (Gaudium et spes, No. 89-90)
The Liturgy of the Hours, Vol. IV, Office of Readings
Tuesday of the 31st Week of Ordinary Time