The leader of the world's 1.3 billion Roman Catholics moved into the basilica on a rolling platform -- a decision, officials said, to spare the 84-year-old Benedict the fatigue of walking the long center aisle.
In his homily, the pope urged people to see past what he described as the superficial “glitter” and commercialism of the Christmas season, and to discover the true joy and light of Jesus' humble birth in a manger.
"Today, Christmas has become a commercial celebration, whose bright lights hide the mystery of God's humility, which in turn calls us to humility and simplicity,” said the pontiff.
“Let us ask the Lord to help us see through the superficial glitter of this season, and to discover behind it the child in the stable in Bethlehem, so as to find true joy and true light," the pope said.
He added: "Manifest your power, O God. In this time of ours, in this world of ours, cause the oppressors' rods, the cloaks rolled in blood and the footgear of battle to be burned, so that your peace may triumph in this world of ours."
On Christmas Day, the ponitff is scheduled to deliver his traditional "Urbi et Orbi" speech, Latin for "to the city and the world."
Earlier, tens of thousands of Christians flocked to Bethlehem, the birthplace of Jesus Christ, located in the West Bank in the Palestinian Territories.
Christmas Eve celebrations took place in and around Manger Square, the central plaza next to the Church of the Nativity, built on the site where it is believed Jesus was born.
In his homily at the Church of the Nativity, Latin Patriarch Fouad Twal, a Palestinian, referred to the "Arab Spring" pro-reform movements and called on Arab leaders to have "wisdom, insight, and a spirit of selflessness toward their countrymen."
He prayed for reconciliation in Syria, Egypt, Iraq, and North Africa.
compiled from agency reports