VATICAN CITY – Pope Benedict XVI, carrying a tall, lit candle, ushered in Christianity's most joyous celebration with an Easter vigil service Saturday night, but voiced fears that mankind is groping in darkness, unable to distinguish good from evil.

Easter for Christians commemorates Christ's triumph over death with his resurrection following his crucifixion.

"Life is stronger than death. Good is stronger than evil. Love is stronger than hate. Truth is stronger than lies," Benedict, wearing white robes in a symbol of new life, told the faithful in a packed St. Peter's Basilica.

Still, Benedict worried in his homily: "The darkness that poses a real threat to mankind, after all, is the fact that he can see and investigate tangible material things, but cannot see where the world is going or whence it comes, where our own life is going, what is good and what is evil."

"The darkness enshrouding God and obscuring values is the real threat to our existence and to the world in general," the pope said.

"If God and moral values, the difference between good and evil, remain in darkness, then all other 'lights,' that put such incredible technical feats within our reach, are not only progress but also dangers that put us and the world at risk," Benedict added.

The service began dramatically. Except for the twinkle of camera flashes, the basilica was almost pitch-black as the thousands of faithful in pews awaited Benedict's arrival through the rear entrance. After aides lit the candle, Benedict climbed aboard a raised platform that was wheeled up the long main aisle to the central altar. The wheeled device is used to save wear and tear on the pontiff, who turns 85 on April 16.

On Sunday morning, Benedict will lead Easter Mass in St. Peter's Square, then deliver a speech from the central balcony of the basilica, at the end of stamina-testing Holy Week appearances.