From the Vatican Information Service blog:
VATICAN CITY, 19 JAN 2011 (VIS) - In his general audience, held this morning in the Paul VI Hall, the Pope dedicated his catechesis to the Week of Prayer for Christian Unity, which is taking place from 18 to 25 January and during which "all those who believe in Christ are invited to come together in prayer, so as to bear witness to the profound ties that unite them and to invoke the gift of full communion".
The Holy Father remarked on "the providential fact that prayer is at the centre of the journey to unity. This", he said, "reminds us once again that unity cannot be a product of mere human efforts, is its above all a gift of God. ... We do not 'construct' unity, God 'constructs' it, it comes from Him, from the mystery of the Trinity".
Benedict recalled how the theme chosen for this year's Week of Prayer "refers to the experience of the first Christian community in Jerusalem, as described in the Acts of the Apostles: 'They devoted themselves to the Apostles' teaching and fellowship, to the breaking of bread and the prayers'".
This quotation identifies "four characteristics defining the first Christian community of Jerusalem", he said, "which still act as pillars for the life of all Christian communities, and constitute the solid foundation on which to continue to construct the visible unity of the Church".
Commenting on the first of these characteristics, the Pope noted that, "even today, the community of believers recognises the norms of its own faith in that reference to the teaching of the Apostles. All efforts to build unity among Christians must, then, involve increasing faithfulness to the 'depositum fidei' handed down to us by the Apostles".
The Holy Father then turned to the second element, "fraternal communion, ... the most tangible expression of unity between disciples and the Lord, especially for the outside world. ... The history of the ecumenical movement has been marked by difficulties and doubts, but it is also a history of fraternity, of co-operation and of human and spiritual sharing, which has significantly altered relations among believers in the Lord Jesus. We are all committed to continuing this journey".
On the subject of the third characteristic, "the breaking of bread", the Holy Father noted that "communion in Christ's sacrifice is the pinnacle of our union with God and, therefore, it also represents the completeness of the unity of Christ's disciples, full communion". In this context he noted also how "the impossibility of sharing the same Eucharist ... also gives a penitential dimension to our prayers. This must be a reason for ever more generous commitment on everyone's part so that, having removed the obstacles to full communion, the day may come when it will be possible to gather around the table of the Lord, together breaking the Eucharistic bread and drinking from the same chalice.
"Finally", he added, "prayer was the fourth characteristic of the early Church in Jerusalem ... Prayer also means opening ourselves to the fraternity that stems from our being children of the one heavenly Father; it means being ready for forgiveness and reconciliation".
"Like the first Christian community of Jerusalem, on the basis of what we already share we must offer a powerful witness - well-founded spiritually and well-supported by reason - of the one God Who revealed Himself and speaks to us in Christ, in order to be bring a message which guides and illuminates the path of modern man, who often lacks clear points of reference. It is important, then, to increase our mutual love every day, striving to overcome the barriers that still exist between Christians, in the knowledge that true inner unity does exist among people who follow the Lord. We must collaborate as much as possible, working together on outstanding questions and, above all, aware that we need the Lord's help on this journey. He must still help us a lot because without Him, alone, without 'abiding in Him', we can do nothing".