The Challenge and Responsibility of Living Our Faith in the Church that is One
By Bishop David J. Malloy
Every time we pray the Nicene Creed at Sunday Mass, we profess our faith in the one, holy, catholic and apostolic Church. The truth that Jesus has established the Church to be one has many implications.
The idea of one true Church challenges the historical divisions of the Church that have come about through the centuries. It also stands in contradiction to the differences in the teachings and theologies that characterize the various Christian churches. 
It is the faith of the Catholic Church, articulated by the Second Vatican Council, that the Church of Christ, “… constituted and organized in the world as a society, subsists in the Catholic Church, which is governed by the successor of Peter and by the Bishops in communion with him, although many elements of sanctification and of truth are found outside of its visible structure. These elements, as gifts belonging to the Church of Christ, are forces impelling toward catholic unity.” (Lumen gentium 8).
Commenting on this important statement by the pope and bishops gathered at Vatican II, Cardinal Marc Ouellet, the current prefect for the Congregation for Bishops, has written, “This is essentially the affirmation of the identity of the Catholic Church expressed in such a way as not to exclude other ecclesial realities.” (“Friends of the Bridegroom,” p. 128).
In short, as Catholics we rejoice that we have been blessed to enter the Catholic Church as the Body of Christ willed and established by Jesus. We also inherit with membership in the Catholic Church the responsibility to testify to the truth of Her uniqueness, even as we acknowledge and rejoice in the elements of grace and truth to be found in other churches.
Obviously this reminds us that the search for unity among the followers of Christ is a task that requires of us the courage to testify clearly, sometimes even against some of the trends and pressures of modern thought. 
We believe, for example, that we do not pick or create our own truth concerning the nature of God, or moral conduct or the reality of heaven and hell. At the same time, we pray to embrace Jesus’ love that seeks a path to unity among the baptized.
The unity of the Church has another element as well. That is the realization of the oneness that we share with the Church and with our fellow Christians throughout the ages and throughout the world today.
There is a temptation to focus our faith only on our own time, only on the Church of our day as we know and perceive her, or only on the problems of faith in modern society. These are important issues. They are the circumstances in which God, in His providence, has decided that we should live and work for our salvation. 
But for every challenge or problem or modern moral question that we face as Christians and Catholics, we need to remind ourselves that we are not the whole. We are part of a wider reality. We are part of the Church of Christ that constantly develops in its understanding of the truth, but in a manner that never contradicts or parts from the essential faith of the men and women who have gone before us.
Likewise, in our day, our vision of the Church must ask how our approach to problems or challenges would be lived out among our brothers and sisters in places where the faith is under persecution or does not have the funding or structure of the Church in our society.
Next week we celebrate the week of prayer for Christian unity. It concludes each year on Jan. 25, the Feast of the Conversion of St. Paul. 
The lack of unity among Christians is a matter of sorrow. So important was this question that Jesus prayed for the unity of His followers on Holy Thursday night. 
Let’s use this opportunity to remind ourselves of the gift, the challenge, and the responsibility of living our faith in the Church that is one.