While Jesus entrusted St. Peter with the keys to the kingdom more than two millennia ago, and his modern-day successor conferred apostolic authority to newly appointed archbishops June 29, it is ultimately God who holds the power to open the church's doors and lead the Christian community forward in its mission of evangelization, Pope Francis said.

Reflecting on the Apostle Peter's liberation from prison after an angel opened his cell, the pope said God "is the one who sets us free and opens the way before us" in his homily during Mass for the feast of Sts. Peter and Paul June 29.

He noted that the Christians Peter sought out after his liberation did not believe he was knocking at their door, mistaking him for an angel.

"This point is significant: the doors of the prison were opened by the Lord’s strength, but Peter then found it hard to enter the house of the Christian community," he said. "How many times have communities not learned this wisdom of the need to open the doors!"

Before 33 newly appointed archbishops gathered in St. Peter's Basilica to receive their palliums -- woolen bands worn by archbishops to symbolize their pastoral authority and unity with the pope -- Pope Francis underscored the model of St. Paul as one who "discovers the grace of weakness."

"When we are weak, he tells us, it is then that we are strong, because we no longer rely on ourselves, but on Christ," the pope said.

Yet he explained that relying on Christ "does not lead to a consoling, inward-looking religiosity like that found in a few movements in the church today," noting instead that St. Paul's encounter with God ignited within him "a burning zeal for evangelization."

Both Sts. Peter and Paul "witnessed first-hand the work of God, who opened the doors of their interior prisons but also the actual prisons into which they were thrown because of the Gospel," he said, as well as the "doors of evangelization, so they could have the joy of encountering their brothers and sisters in the fledgling communities and bring the hope of the Gospel to all."

After the entrance procession, deacons brought out the palliums from the tomb of St. Peter for Pope Francis to bless them. The palliums, made from the wool of lambs blessed by the pope on the feast of St. Agnes -- who is often depicted with a lamb to symbolize purity -- emphasize the role of the archbishop as a pastor who guides and protects his flock.

Pope Francis remained seated during the Mass -- Cardinal Giovanni Battista Re, dean of the College of Cardinals, was the main celebrant at the altar -- but stood during the sign of peace to greet Orthodox Metropolitan Emmanuel Adamakis of Chalcedon, who attended the Mass as part of a delegation from the Ecumenical Orthodox Patriarchate of Constantinople..

The pope invited the metropolitan to sit next to him when he distributed the palliums to the archbishops, who each shook his hand after greeting the pope.

Among the 33 archbishops were Archbishop Christopher J. Coyne of Hartford, Connecticut, and Archbishop Thomas R. Zinkula of Dubuque, Iowa. Both U.S. archbishops brought members of their families with them to Rome to witness them receive their palliums from the pope.

After the Mass, Archbishop Zinkula told Catholic News Service that receiving the pallium is a "huge symbol" of the archbishops' unity with the universal church and the pope, which he said is especially important in light of a growing sense of division in the United States at large and the U.S. church.

A member of the North American synod team, Archbishop Zinkula said that discussions on tensions arose in many synod listening sessions throughout the country, and that the responsibility for overcoming such feelings of division fall to the church's pastors.

"If we're going to be effective in evangelizing in our increasingly secular culture, we've got to be together as a church, and that bishop is at the heart of that," he said, stressing the need for people to seek refuge in the sacraments and particularly the Eucharist "to heal us and help us grow in our faith and love."

The archbishop said the church needs to address its own sense of division, but that it should also play a role in "helping to dissipate that larger tension in society."

Archbishop Coyne also acknowledged increased societal division which "finds its way into the church," but said that the chair of St. Peter remains as a "symbol of unity" for Catholics, "irregardless of who sits in it."

As a result, the church's pastors are called to be "unifiers," the archbishop told CNS. "People are feeling isolated, that's why we want to bring them to communion, people are feeling angry and feel they have meaningless lives, that's why we want to have them know the full meaning of life, which is in Jesus Christ."

"Everything we do as Christians, especially as Catholics, should never be anything that leads to division, anger," but rather action that "brings us together as brothers and sisters," he said.