In his Christmas message to the world Pope Francis called on people to see differences as a source of richness instead of danger and called for reconciliation in places torn apart by conflict.
Security has been tight around the Vatican for the Christmas season, with military jeeps stationed at key access routes and tourists undergoing metal detector and bag searches.
Last week police in southern Italy arrested a Somali man suspected of having been a member of Islamic State and who had threatened to bomb churches in Italy, including St. Peter’s.
"In our day, for many people, life's meaning is found in possessing, in having an excess of material objects," regretted the leader of the world's 1.3 billion Catholics during the Christmas Eve mass.
Pope urges "sharing and giving" in Christmas mass
Assailing the greediness and voraciousness of mankind, Pope Francis asked people not to “lose our footing or slide into worldliness and consumerism".
"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 added.
Pope Francis, who turned 82 earlier this month, is to deliver his sixth "Urbi et Orbi" address on Tuesday, Christmas Day -- when Christians celebrate the birth of Jesus Christ -- to pilgrims gathered in Saint Peter's Square.