89 Since, in virtue of her mission received from God, the Church preaches the Gospel to all men and dispenses the treasures of grace, she contributes to the ensuring of peace everywhere on earth and to the placing of the fraternal exchange between men on solid ground by imparting knowledge of the divine and natural law. Therefore, to encourage and stimulate cooperation among men, the Church must be clearly present in the midst of the community of nations both through her official channels and through the full and sincere collaboration of all Christians—a collaboration motivated solely by the desire to be of service to all. This will come about more effectively if the faithful themselves, conscious of their responsibility as men and as Christians will exert their influence in their own milieu to arouse a ready willingness to cooperate with the international community. Special care must be given, in both religious and civil education, to the formation of youth in this regard.
Source: Gaudium et Spes (Vatican.va)