Pope Benedict XVI warned Thursday that man's refusal to submit to the will of God would lead to the destruction of the world, as he celebrated a mass to mark the 40th anniversary of the conclusion of the Second Vatican Council.
A man who abandons himself to God "does not lose his freedom", Benedict XVI said.
But "if we live against love and against truth - against God - then we are destroying ourselves and we are destroying the world", he warned.
Human history was like "the battle between man and the serpent, the battle between man and the forces of evil and death", he said.
"Man does not have confidence in God," Benedict XVI said. "He nurtures the doubt that God ultimately takes something from his life, that God is a competitor who limits our freedom and that we cannot be human beings without casting him aside."
"But the liberty to be a human being is the liberty of a limited being," he added.
Benedict XVI described the Second Vatican Council as "the most important ecclesiastical event of the 20th century", as he gave the Angelus blessing in Saint Peter's Square on the holiday of the Immaculate Conception of the Virgin Mary.
Since the Council, he said, Mary had guided the Church "on the road of authentic, conciliatory renewal, through tireless work on the faithful interpretation and the implementation of the Second Vatican Council."
Preferring to dedicate his address to the theme of original sin and man's temptation to relinquish God, Benedict XVI made no reference to any current-day issues.
After the Angelus, the pope blessed the Olympic flame which arrived in Italy Wednesday ahead of the Winter Olympics to be held in Turin in February.