Claiming the brotherhood of their respective patron saints --- the apostles Andrew and Peter --- the spiritual leaders of the world's Orthodox and the world's Catholics joined together in prayer and solemnly affirmed their commitment to the full unity of their churches.

Incense and ancient hymns chanted in Greek set the atmosphere as Pope Benedict XVI paid homage to the Orthodox church by attending a Nov. 30 Divine Liturgy celebrated by Ecumenical Patriarch Bartholomew of Constantinople.

The liturgy at the Orthodox Church of St. George in Istanbul marked the feast of St. Andrew, patron of the patriarchate.

The pope and patriarch greeted each other with kisses on the cheek, but then the pope moved to a raised wooden throne at the side of the church while the patriarch celebrated the solemn liturgy.

After the almost three-hour liturgy, Patriarch Bartholomew led Pope Benedict to a balcony overlooking a courtyard. They both blessed the crowd, then the patriarch took the pope's hand and held it aloft as they waved and smiled at the applauding crowd below.

"In the liturgy, we are reminded of the need to reach unity in faith as well as in prayer," the patriarch said in his homily.

"Therefore, we kneel in humility and repentance before the living God and Our Lord Jesus Christ, whose precious name we bear and yet at the same time whose seamless garment we have divided," the patriarch told the pope and other members of the congregation.

"We confess in sorrow that we are not yet able to celebrate the holy sacraments in unity," Patriarch Bartholomew said. "And we pray that the day may come when this sacramental unity will be realized in its fullness."

As the Orthodox faithful processed up for Communion, they bowed to the pope before receiving the consecrated bread and wine.

But one little boy, dressed in a dark suit and tie, stepped out of the line to kiss the pope's ring.

Although the Orthodox church in Turkey has fewer than 5,000 members, Pope Benedict told reporters that the patriarchate's standing in the Orthodox world as the "first among equals" made a visit almost obligatory.

"Numbers, quantity, do not count," the pope told reporters Nov. 28 on the way to Turkey. "It is the symbolic, historical and spiritual weight that counts" and the fact that the patriarchate "remains a point of reference for the whole Orthodox world and, therefore, for all of Christianity."

Addressing the congregation at the end of the liturgy, Pope Benedict said the service was an opportunity "to experience once again the communion and call of the two brothers," Peter and Andrew, chosen by Jesus to be his apostles and sent to different cities to preach the same Gospel.

The fact that the brothers also had different roles within the Christian community, with Peter and his successors in Rome having a "universal responsibility," has "unfortunately given rise to our differences of opinion, which we hope to overcome, thanks also to the theological dialogue which has been recently resumed," Pope Benedict said.

While Orthodox generally recognize the importance of the church of Rome, they object to the way in which popes have tried to exercise direct jurisdiction over all Christian communities.

Pope Benedict said he wanted to "recall and renew" the invitation issued by Pope John Paul II for a discussion among Christians on possible ways for exercising the papal ministry to serve the unity of all Christians.

"It is only through brotherly communion between Christians and through their mutual love that the message of God's love for each and every man and woman will become credible," the pope said.

Like the patriarch, he expressed his sadness at the fact that although they share the same faith and recognize the validity of each other's sacraments, Catholics and Orthodox cannot regularly share each other's Eucharist.

"May our daily prayer and activity be inspired by a fervent desire not only to be present at the Divine Liturgy, but to be able to celebrate it together, to take part in the one table of the Lord, sharing the same bread and the same chalice," the pope said.

At the end of the liturgy, he gave Patriarch Bartholomew a chalice as a gift.

The patriarch, in turn, gave the pope a Book of the Gospels, expressing his hope that Catholics and Orthodox would be imitators of Christ and would allow love, unity and peace to prevail.

After the liturgy, the pope and patriarch signed a joint declaration committing their churches to continuing theological dialogue and greater practical cooperation, especially in promoting Christian values in increasingly secularized societies.

They also expressed their concern for the poor and for victims of violence --- especially in the Middle East --- and terrorism and those whose religious freedom is not recognized fully.

In the afternoon, the pope continued his ecumenical visits, meeting Armenian Orthodox Patriarch Mesrob II and Syrian Orthodox Metropolitan Filuksinos Yusuf Cetin.

---CNS