The future of humanity depends on economic policies that protect the environment, support human dignity and promote justice, said several participants at a Vatican symposium.
Christians who are too serious and gloomy have the Holy Spirit missing from their lives, Pope Francis said.
Be meek and open to the Spirit and don't fight the joy and unexpected newness he brings, the pope said Tuesday during his early morning Mass at the Domus Sanctae Marthae.
People who think they can and do know everything won't be able to understand God, he said in his homily, according to a report by Vatican Radio.
Always be merciful, just like Jesus, who came to forgive, not condemn, Pope Francis told new priests.
"Always have in front of your eyes the example of the Good Shepherd, who didn't come to be served, but to serve and to look for and save those who were lost," he said in his homily Sunday, the World Day of Prayer for Vocations.
The pope's remarks came during an ordination Mass in St. Peter's Basilica, where the pope ordained 13 new priests.
Pope Francis signed a decree Friday recognizing a miracle attributed to the intercession of Pope Paul VI and authorized publication of the Oct. 19 beatification date.
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.