3 At the Second Vatican Council, the Catholic Church committed herself irrevocably to following the path of the ecumenical venture, thus heeding the Spirit of the Lord, who teaches people to interpret carefully the "signs of the times" . The experiences of these years have made the Church even more profoundly aware of her identity and her mission in history. The Catholic Church acknowledges and confesses the weaknesses of her members, conscious that their sins are so many betrayals of and obstacles to the accomplishment of the Saviour's plan. Because she feels herself constantly called to be renewed in the spirit of the Gospel, she does not cease to do penance. At the same time, she acknowledges and exalts still more the power of the Lord, who fills her with the gift of holiness, leads her forward, and conforms her to his Passion and Resurrection. Taught by the events of her history, the Church is committed to freeing herself from every purely human support, in order to live in depth the Gospel law of the Beatitudes. Conscious that the truth does not impose itself except "by virtue of its own truth, as it makes its entrance into the mind at once quietly and with power", she seeks nothing for herself but the freedom to proclaim the Gospel. Indeed, her authority is exercised in the service of truth and charity. I myself intend to promote every suitable initiative aimed at making the witness of the entire Catholic community understood in its full purity and consistency, especially considering the engagement which awaits the Church at the threshold of the new Millennium. That will be an exceptional occasion, in view of which she asks the Lord to increase the unity of all Christians until they reach full communion. The present Encyclical Letter is meant as a contribution to this most noble goal. Essentially pastoral in character, it seeks to encourage the efforts of all who work for the cause of unity.
Source: Ut Unum Sint (Vatican.va)