The Church has endured for 2000 years. Like the mustard seed in the Gospel, she has grown and become a great tree, able to cover the whole of humanity with her branches [cf. Mt 13:31-32]. The Second Vatican Council, in its Dogmatic Constitution on the Church, thus addresses the question of membership in the Church and the call of all people to belong to the People of God: "All are called to be part of this Catholic unity of the new People of God ... And there belong to it or are related to it in various ways, the Catholic faithful as well as all who believe in Christ, and indeed the whole of mankind, which by the grace of God is called to salvation." Pope Paul VI, in the Encyclical Ecclesiam Suam illustrates how all mankind is involved in the plan of God, and emphasizes the various circles of the dialogue of salvation.
Continuing this approach, we can also appreciate more clearly the Gospel parable of the leaven [cf. Mt 13:33]: Christ, like a divine leaven, always and ever more fully penetrates the life of humanity, spreading the work of salvation accomplished in the Paschal Mystery. What is more, he embraces within his redemptive power the whole past history of the human race, beginning with the first Adam. The future also belongs to him: "Jesus Christ is the same yesterday and today and for ever" [Heb 13:8]. For her part the Church "seeks but a solitary goal: to carry forward the work of Christ himself under the lead of the Holy Spirit, the Paraclete. And Christ entered this world to give witness to the truth, to rescue and not to sit in judgment, to serve and not to be served."
Therefore, ever since the apostolic age, the Church's mission has continued without interruption within the whole human family. The first evangelization took place above all in the region of the Mediterranean. In the course of the first millennium, missions setting out from Rome and Constantinople brought Christianity to the whole continent of Europe. At the same time they made their way to the heart of Asia, as far as India and China. The end of the fifteenth century marked both the discovery of America and the beginning of the evangelization of that great continent, North and South. Simultaneously, while the sub-Saharan coasts of Africa welcomed the light of Christ, Saint Francis Xavier, Patron of the Missions, reached Japan. At the end of the eighteenth century and the beginning of the nineteenth, a layman, Andrew Kim, brought Christianity to Korea. In the same period the proclamation of the Gospel reached Indochina, as well as Australia and the Islands of the Pacific.
The nineteenth century witnessed vast missionary activity among the peoples of Africa. All these efforts bore fruit which has lasted up to the present day. The Second Vatican Council gives an account of this in the Decree Ad Gentes on Missionary Activity. After the Council the question of missionary work was dealt with in the Encyclical Redemptoris Missio, in the light of the problems of the missions in these final years of our century. In the future too, the Church must continue to be missionary: indeed missionary outreach is part of her very nature. With the fall of the great anti-Christian systems in Europe, first of Nazism and then of Communism, there is urgent need to bring once more the liberating message of the Gospel to the men and women of Europe. Furthermore, as the Encyclical Redemptoris Missio affirms, the modern world reflects the situation of the Areopagus of Athens, where Saint Paul spoke. Today there are many "areopagi", and very different ones: these are the vast sectors of contemporary civilization and culture, of politics and economics. The more the West is becoming estranged from its Christian roots, the more it is becoming missionary territory, taking the form of many different "areopagi".
The future of the world and the Church belongs to the younger generation, to those who, born in this century, will reach maturity in the next, the first century of the new millennium. Christ expects great things from young people, as he did from the young man who asked him: "What good deed must I do, to have eternal life?" [Mt 19:16]. I have referred to the remarkable answer which Jesus gave to him, in the recent Encyclical Veritatis Splendor, as I did earlier, in 1985, in my Apostolic Letter to the Youth of the World. Young people, in every situation, in every region of the world, do not cease to put questions to Christ: they meet him and they keep searching for him in order to question him further. If they succeed in following the road which he points out to them, they will have the joy of making their own contribution to his presence in the next century and in the centuries to come, until the end of time: "Jesus is the same yesterday, today and for ever".
In conclusion, it is helpful to recall the words of the Pastoral Constitution Gaudium et Spes: "The Church believes that Christ, who died and was raised up for all, can through his Spirit offer man the light and the strength to measure up to his supreme destiny. Nor has any other name under heaven been given to man by which it is fitting for him to be saved. She likewise holds that in her most benign Lord and Master can be found the key, the focal point, and the goal of all human history. The Church also maintains that beneath all changes there are so many realities which do not change and which have their ultimate foundation in Christ, who is the same yesterday and today and for ever. Hence in the light of Christ, the image of the unseen God, the firstborn of every creature, the Council wishes to speak to all men in order to illuminate the mystery of man and to cooperate in finding the solution to the outstanding problems of our time."