Pope Francis, at a Mass for poor and homeless people, has warned against the "anaesthetised consciences" of those who see the needy as bothersome instead of as brothers and sisters to be helped.
About 6000 homeless, poor and displaced people from a dozen European countries and Africa were brought to the Vatican by charity groups to have their own special day in the Catholic Church's Jubilee Year of Mercy, which ends next week.
"We should be worried when our consciences are anaesthetised and we no longer see the brother or sister suffering at our side, or notice the grave problems in our world, which become a mere refrain familiar from the headlines on the evening news," he said in his homily on Sunday.
Those in attendance were given headphones so they could hear a simultaneous translation of the Pope's words, a rarity at liturgical services in the basilica.
The world's needy, the Pope said, should be seen as "concrete people, not useless objects but precious persons".
Francis, the first Latin American Pope - who has made defence of the poor a hallmark of his pontificate - told the well-off in society:
"There is no peace in the homes of the prosperous as long as justice is lacking in the home of everyone.
"It is the symptom of a spiritual sclerosis when we are only interested in objects to be produced rather than in persons to be loved. This is the origin of the tragic contradiction of our age: as progress and new possibilities increase, which is a good thing, less and less people are able to benefit from them," he said.
Since his election in March 2013, Francis has taken steps to help the homeless in the area around the Vatican, including opening shelters just off St Peter's Square where they can bathe, get haircuts, medical referrals and information on social services.
During the Jubilee Year, which began on December 8, the world's 1.2 billion Roman Catholics have been urged to carry out acts of mercy and mutual forgiveness and to make pilgrimages to Rome or to local churches.
Homeless people were the guests of honour on Saturday night at a special benefit concert in the Vatican conducted by Oscar-winning composer Ennio Morricone.