On October 11, 1962, Pope John XXIII opened the Second Vatican council with an address in which he explained the decision to hold a council, the purpose of the council, and how the Church ought to interact with the modern world.
The major interest of the Ecumenical Council is this: that the sacred heritage of Christian truth be safeguarded and expounded with greater efficacy.
That doctrine embraces the whole man, body and soul. It bids us live as pilgrims here on earth, as we journey onwards towards our heavenly homeland.
It demonstrates how we must conduct this mortal life of ours. If we are to achieve God’s purpose in our regard we have a twofold obligation: as citizens of earth, and as citizens of heaven. That is to say, all men without exception, both individually and in society, have a life-long obligation to strive after heavenly values through the right use of the things of this earth. These temporal goods must be used in such a way as not to jeopardize eternal happiness.
True enough, Christ our Lord said: “Seek first the kingdom of God and His justice,” and this word “first” indicates what the primary direction of all our thoughts and energies must be. Nevertheless, we must not forget the rest of Our Lord’s injunction: “and all these things shall be given you besides.” Thus the traditional as well as the contemporary Christian approach to life is to strive with all zeal for evangelical perfection, and at the same time to contribute toward the material good of humanity. It is from the living example and the charitable enterprise of such Christians as these that all that is highest and noblest in human society takes its strength and growth.
If this doctrine is to make its impact on the various spheres of human activity—in private, family and social life—then it is absolutely vital that the Church shall never for an instant lose sight of that sacred patrimony of truth inherited from the Fathers. But it is equally necessary for her to keep up to date with the changing conditions of this modern world, and of modern living, for these have opened up entirely new avenues for the Catholic apostolate.