"[...]
The second part of the Council was much more extensive. There appeared with great urgency the issue of today's world, the modern age, and the Church; and with it, the issues of responsibility for the building up of this world, of society, responsibility for the future of this world and eschatological hope, the ethical responsibility of Christians and where we look for guidance; and then religious freedom, progress, and relations with other religions. At this moment, all the parties of the Council really entered into the discussion, not just America, the United States, with its powerful interest in religious freedom. In the third session the Americans told the Pope: we cannot go home without bringing a declaration on religious freedom voted by the Council. The Pope, however, had the firmness and the decision, the patience, to take the text to the fourth session, for the sake of greater discernment and the fuller consent of the Council Fathers. I mean: it was not only the Americans who intervened forcefully in the unfolding of the Council, but also Latin America, well aware of the extreme poverty of its people, on a Catholic continent, and the responsibility of the faith for the situation of these people. Likewise, Africa and Asia saw the need for interreligious dialogue; problems arose which we Germans – I have to admit – had not foreseen. I cannot describe all of this now. The great document Gaudium et Spes analyzed very well the issue of Christian eschatology and worldly progress, and that of responsibility for the society of the future and the responsibility of Christians before eternity, and in this way it also renewed a Christian ethics, the foundations of ethics. But – let us say unexpectedly – alongside this great document there arose another document which responded in a more synthetic and more concrete way to the challenges of the times, and this was the Declaration Nostra Aetate. From the beginning our Jewish friends were present, and they said, primarily to us Germans, but not to us alone, that after the tragic events of the Nazi period, the Nazi decade, the Catholic Church had to say something about the Old Testament, about the Jewish people. They said: even if it is clear that the Catholic Church is not responsible for the Shoah, it was Christians for the most part who committed those crimes; we need to deepen and renew Christian awareness of this, even though we know full well that true believers have always resisted these things. Thus it was clear that our relationship with the world of the ancient People of God needed to be an object of reflection. Understandably, too, the Arab countries – the bishops of the Arab countries – were unhappy about this: they feared somewhat a glorification of the State of Israel, which naturally they did not want. They said: fine, a truly theological statement about the Jewish people is good, it is necessary, but if you speak about that, speak of Islam too; only then will there be a balance; Islam too is a great challenge and the Church also needs to clarify her relationship with Islam. This was something that, at the time, we did not much understand: a little, but not much. Today we know how necessary it was.
When we began to work also on Islam, we were told that there were also other world religions: the whole of Asia! Think of Buddhism, Hinduism…. And so, instead of a declaration as initially conceived, concerning only the People of God in the Old Testament, a text was created on interreligious dialogue, anticipating what only 30 years later would be demonstrated in all its intensity and importance. I cannot enter now into this theme, but if one reads the text, one sees that it is very dense and prepared truly by people who were familiar with the realities, and it indicates briefly, in a few words, what is essential. Likewise it indicates the foundation of dialogue, in difference, in diversity, in faith, on the unicity of Christ, who is one, and it is not possible for a believer to think that religions are all variations on a single theme. No, there is one reality of the living God, who has spoken, and there is one God, one incarnate God, thus one word of God, that is truly God's word. But there is religious experience, with a certain human light from creation, and therefore it is necessary and possible to enter into dialogue, and thus to become open to one another and to open everyone to the peace of God, the peace of all his sons and daughters, the peace of his entire family.
Therefore, these two documents, on religious freedom and Nostra Aetate, linked to Gaudium et Spes, make a very important trilogy whose importance has been demonstrated only after decades, and we are still working to understand better the interlinked realities of the unicity of God's revelation, the unicity of the one God incarnate in Christ, and the multiplicity of religions, by which we seek peace and also hearts that are open to the light of the Holy Spirit, who illumines and leads to Christ.
[...]"