When Ecumenical Patriarch Bartholomew of Constantinople meets Pope Francis, they will discuss the "diminishing Christian minorities in the Middle East."
While it is true that the church is made up of sinners, it is also true that Christ has made the church holy and he can make sinners holy, too, Pope Francis said.
To honor the sacrifice of those killed for their faith in the 20th century, Christians today must renew their commitment to reconciliation and full Christian unity, Pope Francis said.
"Just as in the ancient church the blood of the martyrs became the seed of new Christians, so in our day the blood of many Christians has become the seed of unity," the pope told Catholicos Karekin II of Etchmiadzin, patriarch of the Armenian Apostolic Church.
The issues dividing Christian communities have changed over the past 50 years, but a Philadelphia archdiocesan priest working in ecumenical dialogue at the Vatican is confident that Christian unity is possible.
"We are people of hope. We trust we have the same Scriptures, the same belief in Christ," said Msgr. Gregory Fairbanks, an official at the Pontifical Council for Promoting Christian Unity.
Never forget to pray, even while commuting, taking a walk or when waiting in line, Pope Francis said.
And don't just stick to prayers memorized from childhood, but include heartfelt requests and pleas for help, advice and guidance, he said.
The Vatican has effectively addressed the "worldwide scourge" of clerical sexual abuse over the past decade, a United Nations panel heard Tuesday.
Christianity is not a school of ideas or a collection of beautiful temples and lovely art; it is a living people who follow Jesus and give witness to him every day, Pope Francis said.
"Am I a Christian giving witness to Jesus or am I a simple numerary of this sect," unable to let the Holy Spirit "drive me forward in my Christian vocation?" he asked in his homily at Mass Tuesday in the Domus Sanctae Marthae, where he lives.
"A Christian who doesn't give witness is unfathomable," he said, according to a report by Vatican Radio.
A U.N. committee on torture repeatedly asked Vatican officials about efforts to investigate allegations of clerical sex abuse, to punish offenders and to cooperate with civil authorities.
The new sex abuse commission sets sights on "superiors of the church [who] have not fulfilled their obligations to protect children."
The number of Catholics in the world and the number of priests, permanent deacons and religious men all increased in 2012, while the number of women in religious orders continued to decline, according to Vatican statistics.
The number of candidates for the priesthood also showed its first global downturn in recent years.
The statistics come from a recently published Statistical Yearbook of the Church, which reported worldwide church figures as of Dec. 31, 2012.