Pope Benedict XVI arrives in St Peter's square to celebrate a Palm Sunday mass at the Vatican, Sunday, 17 April 2011. (AP)
More than 40,000 pilgrims filled a sun-drenched St Peter's Square for Palm Sunday mass as Pope Benedict XVI urged the faithful to reach beyond technology in the "quest for God's face".
Cardinals, bishops, priests and lay Catholics carrying traditional palm branches were assembled as the popemobile slowly bore the pontiff, clad in red vestments symbolising life, to the outdoor altar set up at the top of the steps to St Peter's Basilica.
A smiling Benedict, who turned 84 on Saturday, appeared well as he blessed the crowds pressing against metal barricades.
Palm Sunday recalls Jesus' triumphal entry in Jerusalem preceding his arrest and crucifixion.
"Of ourselves, we are too weak to lift up our hearts to the heights of God," the German pontiff said in his homily. "God himself must draw us up, and this is what Christ began to do on the cross." He said such uplifting required "clean hands, a pure heart, the rejection of falsehood (and) the quest for God’s face."
Technological advances "are liberating and contribute to the progress of mankind only if they are joined to these attitudes," warned the leader of the world's 1.1 billion Catholics.
"Mankind has managed to accomplish so many things: we can fly! We can see, hear and speak to one another from the farthest ends of the earth. And yet the force of gravity which draws us down is powerful," he said.
"Our limitations have also remained: we need but think of the disasters which have caused so much suffering for humanity in recent months," he said, praying "that we may be part of the generation which seeks God."
Along with the good, the pope added, "Our possibilities for evil have increased and appear like menacing storms above history."