Rite and Reason:The annual Week of Prayer for Christian Unity is a time for the churches to strengthen their commitment to the search for full communion, writes Ian Ellis.
Each person who takes part in the liturgical events of this special octave is called to take that commitment more seriously and to pursue it with increased vigour.
Indeed, encouragement in that enterprise is to be found by looking back at the ecumenical journey travelled so far. It is not all success, but it does show a growth in mutual understanding and, over the years, a transformed atmosphere.
There have, of course, been ecumenical crises along the way, not least the controversial Dominus Iesus document of 2000 in which the Vatican referred to Protestant churches as not being churches "in the proper sense".
That sentiment was reiterated by the Vatican last year and so the storm has not yet been fully weathered. However, such crises aside, Christians are working together more closely today than ever before and, in so doing, the foundations for future full communion are strengthened.
Last October, a remarkable ecumenical study day was held in Dublin in which much of the ecumenical journey so far was surveyed, and there really was encouragement. The main subject was that of the bilateral dialogues between the Christian world communions and the occasion was greatly helped by the presence of Dr Mary Tanner, the top-ranking Anglican ecumenist and one of the presidents of the World Council of Churches.
While Dr Tanner gave a comprehensive survey of the bilateral dialogues, she also identified the obstacles that remain in the ecumenical journey, thereby clearly setting forth the serious challenges facing ecumenists.
Among those obstacles, two were really fundamental: Do the churches have a shared understanding of what the visible unity of the church would look like and are there competing models? What are the constitutive elements of visible unity?
The truth is that the churches do not have a shared understanding of visible unity and of what the one church's constitutive elements are. There are different, and perhaps competing, models.
Churches that are more congregational in outlook tend to view Christian unity as largely about sharing the fundamentals of the faith and co-operating in outreach, while churches that are more heavily structured tend to view unity in terms of more wide-ranging, formal doctrinal agreement and the mutual acceptance of ministerial and authority structures.
It is the latter churches that have found achieving real unity the most difficult. Ironically, the divisions in Christianity are to a large extent being sustained by disagreement over the role of those who are there precisely to serve the faithful.
How are the churches to get past this intractable issue? Perhaps the first thing they need to do is to take more to heart the truth that real authority lies in true service and that true service is about giving of oneself for the other. Christ spoke with authority not because of any religious office or position but because of his utter self-giving, revealing himself as the way, the truth and the life.
Dr Tanner told the study day a tale of two cardinals, both of whom she had recently heard speaking. Cardinal Avery Dulles, the renowned professor at Fordham University, New York, had said theological conversations between the churches had run their course. The Vatican's Cardinal Walter Kasper had urged an intensification of dialogue. Perhaps the two opposing perspectives reveal the heart of the matter: ecumenical dialogue is fundamentally in need of new direction and new life.
The much-needed new energy will come when an ecumenism of ecclesial self-renunciation is discovered; that is, when the churches see more clearly that their authority rests on the depth of self-renouncing service they give.
Such is the kind of "incarnational" vision of church life that Church of Ireland primate Archbishop Alan Harper articulated in an interview with the Church of Ireland Gazette last year.
New ecumenical impetus will be found when the churches focus less on themselves internally and more on the real spiritual and material needs of humanity. Thus the power of Christ will be more clearly revealed.
Canon Ian Ellis is rector of Newcastle, Co Down, and editor of the Church of Ireland Gazette