Pope Francis told Catholic clergy on Saturday to leave their comfort zones and smug surroundings and reach out to serve the poor and needy.
"We cannot keep ourselves shut up in parishes, in our communities, when so many people are waiting for the Gospel," he said in the sermon of a Mass in Rio's cathedral on the penultimate day of his trip to Brazil.
Since his election in March as the first non-European pope in 1,300 years, Francis has been prodding priests, nuns and bishops to think less about their careers in the Church and listen more to the cries of those hungry to fill both material and spiritual needs.
"It is not enough simply to open the door in welcome, but we must go out through that door and meet the people!" he said.
Known as the "slum cardinal" in his native Argentina because of his austere lifestyle and visits to poor areas, Francis made a clarion call to clergy to take risks and go out among the faithful who need them most.
"It is in the 'favelas' and 'villas miseria' that one must go to seek and to serve Christ," he said, quoting the late Mother Teresa of Calcutta and using the terms used in Brazil and Argentina for shantytowns.
Francis has set the tone in the Vatican, rejecting the lush papal residence his predecessors used in the Apostolic Palace and living instead in a small suite in a Vatican guest house, and often eating in the common dining room.
In some of his early outings from the Vatican he has chosen to visit those in need. Shortly after his election, he visited a jail for minors and his first trip outside Rome was to the southern Italian island of Lampedusa to pay tribute to immigrants who have died trying to get to Italy.
Millions of people have turned out to see the Argentine pope since his arrival on Monday for events surrounding an international jamboree of Catholic youth, known as World Youth Day.
In his sermon in the ultra-modern cone-shaped cathedral, Francis hammered home the need for priests and nuns to go out on the streets and into the rough neighborhoods.
"Let us courageously look to pastoral needs, beginning on the outskirts, with those who are farthest away, with those who do not usually go to church," he said.
On Friday night at a rally on Rio's famed Copacabana beach, he urged young people to change a world where food is discarded while millions go hungry, where racism and violence still affront human dignity and where politics is more associated with corruption than service.
He ordered his open-sided popemobile to stop numerous times along his 1.8-mile (3-km) route so he could kiss babies and shake hands. He got out several times to walk along the route, making his security detail nervous again.
Since his election in March, the pope has taken strong stands in defense of the environment and has several times said that financial speculation and corruption kept millions of people hungry.
During a visit to a Rio slum on Thursday, he urged residents to not lose trust and not let their hopes to be extinguished. Many young people in Brazil saw this as his support for peaceful demonstrations to bring about change.
At the slum, he issued the first social manifesto of his young pontificate, saying that the world's rich must do much more to wipe out vast inequalities between the haves and the have-nots.
The first Latin American pope is clearly relishing the enthusiasm at a time when the Church, which once was an unrivalled religious bastion on the continent, is grappling to hold onto faithful.
The final event of World Youth Day is Sunday, when Francis presides at a closing Mass before returning to Rome that evening.