“These questions, however, have to be answered, from the point of view of systematic theology at least, by placing them within a much more radical framework, namely that of the fundamental question: Is the structure of the Christian Church in light of the gospel, monarchial or collegial? This question is undoubtably radical because it is asked, on the one hand, with the whole Christian people in mind and, on the other, from the point of view of what the Lord himself taught, that is, in the light of the gospel of Christ as a whole.
We may go further and say that, if the structure of the Church is conditioned by and subject to the norm of the gospel of Christ, we must base our argument less on the isolated descriptions or ideas of the Church which occur almost accidentally in the New Testament…and more on the general spirit of the words of the Lord as the origin of those images of the Church. That essentially new elemnt in the teaching of the Lord which distinguishes it from teaching contained in all the religions and ideaologies that have so far arisen in the history of man is the doctrine of the Trinity. This is the differentia specifica of Christianity.
In light of this faith in the Trinity, the Christian teaching about God’s being, the creation of the world and the cosmic mestaphysical order of the universe has always been different from that of other religions or ideaologies. It has, in a word, been trinitarian. The idea of the Trinity is central, not only in the doctrine of the Christian Church, but also-and in the first place-in the teaching of the Lord himself. If this is so, then surely it is bound to inspire the whole task of the Christian Church to give a new structure to the created world. This brings us to the question of the relationship between the doctrine of the Trinity and Christology.
At the most holy moment of his life on earth and just before he left this world, Christ prayed to his Father and at the same time expressed his most fervent desire: ‘I do not pray for these only, but also for those who believe in me through their word, that they may be one; even as thou, Father, art in me, and I in thee.’ (John 17.20f.)
It is perhaps symptomatic that, in an attempt to stress the holiness of the ecumenical intention, these words are quoted nowaday at almost every meeting between Christians of different denominations. yet we usually think very little about these important words afterwards. The phrase ‘that they may be one’ expresses the practical and immediate aims of ecumenism better than the idea which follows, namely ‘as thou Father, art in me…’. But these words become even more meaningful perhaps if we remember that this exemplary mode of unity within the Trinity is the basic presupposition for the unity of the Church which we hope will be achieved. the importance of the whole passage is even further emphasized by the fact that Christ did not have a definite gorup of people, such as the apostles in mind when he spoke these words, but rather all those who believed in him and would believe in him throughout history. It is this universal validity of the moral principle that is expressed here which gives it its distinctive and normative character. This is why it must constitute the basic and first ecclesiolgy premise for all theological thinking at all times.
It is clear therefore that there must be a direct relationship between the doctrine of the Trinity and ecclesiology, a relationship expressed in fact in the striking parallel that exists between the fundamental theological questions of the Church’s Trinitarian and ecclesiological teaching. If the inner interrelationships that exist in the historical development of dogma in the Church have existed since the earliest times are borne in mind, it is not difficult to recognize that the main problem confronting all theological thinking throughout the history of the Church has always been the same-the fundamental question of the relationship between unity and multiplicity.