LOURDES, France (AP) -- Pope Benedict XVI celebrated Mass on Sunday at the Lourdes shrine renowned for miracles, telling tens of thousands of faithful they should hold onto hope in a world full of evil, torture, suffering and injustice.
About 50,000 pilgrims, singing hymns and some shouldering a life-sized crucifix, gathered on a rain-soaked field known as the Lourdes prairie for the Mass marking the 150th anniversary of a peasant girl's religious visions. Millions visit the spot each year to pray for miracles of physical or spiritual healing.
The pope urged the pilgrims to remain hopeful in the face of evil and hardship.
"The power of love is stronger than the evil which threatens us," Benedict said.
The pope is making a three-day pilgrimage to the sanctuary, which is visited each year by 6 million pilgrims. Many believe miracles can be delivered by Bernadette Soubirous - the 14-year-old daughter of peasants who in 1858 told local clergy she had seen the Virgin Mary appear to her at the Massabielle riverside grotto.
"For 150 years, pilgrims have never ceased to come to the grotto of Massabielle to hear the message of conversion and hope which is addressed to them. And we have done the same," Benedict said, reading his homily from a platform where an altar was set up.
The Catholic church's liturgy on Sept. 14 is focused on the symbol of the cross.
Benedict told the crowd that the cross initiates the faithful into the mysteries of Christian faith, including that "there is a love in this world that is stronger than death, stronger than our weaknesses and sins."
Jesus in his death by crucifixion "took upon himself the weight of all the sufferings and injustices of our humanity," the pope said. "He bore the humiliation and the discrimination, the torture suffered in many parts of the world by so many of our brothers and sisters for the love of Christ."
The 81-year-old pontiff said the faithful should live their lives in "invincible hope, refusing to believe those who claim that we are trapped in the fatal power of our destiny."
Benedict spent Saturday night at a hermitage, after praying at the Lourdes grotto where a spring of water broke through the ground during the months Bernadette saw the apparitions of Mary.
The pope drank some of the water in the grotto. But he had said Friday he was not coming to seek miracles at Lourdes, which he has likened to a citadel of hope.
Countless believers in the water's healing power come to Lourdes to drink or bathe in it, and bring home flasks and even gas-can sized plastic containers of the spring's water.
French bishops came to Lourdes for a meeting later Sunday with the pope, who wants to shore up flagging faith in the traditionally Roman Catholic country where Mass attendance is very low.
Among the pilgrims at Sunday's Mass was a group of Spanish students who had slept on mats on the floor of Lourdes' basilica.
"In Lourdes you can feel the Catholic faith more strongly than in other places," said Ines Belinchon, a high-school student on her fifth trip to Lourdes, where she has often come to help the sick.
Associated Press writer Angela Doland in Lourdes contributed to this report.