Pope Francis decried consumerism and urged people to seek a simpler less materialistic life at a Christmas Eve Mass in the Vatican.
Marking the sixth Christmas of his papacy, Francis led a service for nearly 10,000 people in St. Peter's Basilica for the traditional event.
The pope, 82, said Jesus, born in poverty in a stable, should make everyone especially those who have become "greedy and voracious" reflect on the real meaning of life.
"... Let us ask ourselves: Do I really need all these material objects and complicated recipes for living? Can I manage without all these unnecessary extras and live a life of greater simplicity?" Francis said.
"In our day, for many people, life's meaning is found in possessing, in having an excess of material objects. An insatiable greed marks all human history, even today, when, paradoxically, a few dine luxuriantly while all too many go without the daily bread needed to survive," he said.
Security has been tight this Christmas in Rome and around the Vatican.
A Somali man suspected of being a member of Islamic State threatened to bomb churches in Italy, including St. Peter's. He was arrested last week.
Defending the poor has become a hallmark of the pope's papacy.
The Vatican said on Saturday he had given Rome's homeless a new clinic in St. Peter's Square where they can receive free medical care, as a gift.
More than 16,000 homeless are estimated in Rome, according to Catholic charity Caritas.
In recent years, the homeless have been congregating near the Vatican, especially at night where they cluster under arches and arcades to sleep.
The pope will deliver his twice-yearly message from the main balcony of St. Peter's Basilica on Christmas Day.