"The church is the bride of Christ, who makes her holy and beautiful by his grace," the pope said Jan. 20 before praying the Angelus with visitors gathered in the rain in St. Peter's Square.
Even though the church is Christ's bride, he said, the fact that the church is made up of human beings means that it always needs purification.
"One of the most serious faults that disfigures the face of the church," the pope said, is the sin "against her visible unity, particularly the historical divisions that have separated Christians and still have not been overcome completely."
Pope Benedict said the Jan. 18-25 Week of Prayer for Christian Unity was a time for all Christians to reawaken their desire and their prayerful commitment to full communion.
He said that the Dec. 28-Jan. 2 pilgrimage sponsored by the Taize ecumenical community of monks, who brought tens of thousands of young Christians to Rome from all over Europe, was "a moment of grace when we were able to experience the beauty of being one in Christ."
The reflections for the 2013 Week of Prayer for Christian Unity were prepared by young people in India and showed a particular concern for the work Christians can and do accomplish together to fight discrimination in their country and around the world.
The pope said the young Indians "call us to walk decisively toward the visible unity of all Christians and to overcome, as brothers and sisters in Christ, every type of unjust discrimination."
Also during his Angelus address, Pope Benedict urged prayers and action for peace in the world, "so that in the various conflicts underway, the massacre of defenseless civilians would cease, there would be an end to every form of violence and people would find the courage for dialogue and negotiation."