Pope Benedict XVI has strongly criticized atheism and blamed it for bringing about the "greatest forms of cruelty and violations of justice" ever known in history.
In the second encyclical of his papacy, the head of the world's one billion Catholics also criticized modern-day Christianity, saying its focus on individual salvation had ignored Jesus' message that true Christian hope involves salvation for all.
In the 76-page document titled "Spe Salvi," or "Saved by Hope," Benedict said that many people rejected religious faith because they no longer found the prospect of an eternal after-life attractive.
Instead, they had put their faith in human reason and freedom in the hope that the "kingdom of man" would emerge.
In his scholarly analysis, the 81-year-old pontiff said that these ideas had originated during two periods of political upheaval – the French and Communist revolutions.
While Benedict came down heavily on Karl Marx and the 19th and 20th century atheism spawned by his revolution, the pope acknowledged that both were responding to the deep injustices of the time.
Marxism, Benedict wrote, had left behind "a trail of appalling destruction" because it failed to realize that man could not be "merely the product of economic conditions." For man to be redeemed, he also needs God's unconditional love.
"It is no accident that this idea (Marxism/Atheism) has led to the greatest forms of cruelty and violations of justice, rather, it is grounded in the intrinsic falsity of the claim", he wrote. "A world which has to create its own justice is a world without hope."
Benedict also cited Vladimir Lenin, the founder of the Soviet Union, and the "intermediate phase" of dictatorship that Marx saw as necessary in the revolution.
"This 'intermediate phase' we know all too well, and we also know how it then developed, not ushering in a perfect world, but leaving behind a trail of appalling destruction," the pope wrote.
Commenting on the pope's latest encyclical, Monsignor Robert Wister, professor of church history at Seton Hall University in the United States, explained that the pope's concern "is that you have secularizing forces that are trying to eliminate religion from public and private life."
"In most countries, political Marxism is dead [but] philosophical Marxism is very much alive and it fuels the secularizing philosophy often seen in Europe and North America," Wister said, according to the Associated Press.
At the same time, Benedict also looked critically at the way modern Christianity had responded to the times, saying such a "self-critique" was also necessary.
"We must acknowledge that modern Christianity, faced with the successes of science in progressively structuring the world, has to a large extent restricted its attention to the individual and his salvation," the pope wrote. "In doing so, it has limited the horizon of its hope and has failed to recognize sufficiently the greatness of its task."
The Christian concept of hope and salvation, the pontiff stated, was not always so individual-centric.
Quoting scripture and theologians, Benedict said salvation had in the earlier church been considered "communal" - illustrating his point by using the case of monks in the Middle Ages who cloistered themselves in prayer not just for their own salvation but for that of others.
"How could the idea have developed that Jesus' message is narrowly individualistic and aimed only at each person singly? How did we arrive at this interpretation of the 'salvation of the soul' as a flight from responsibility for the whole, and how did we come to conceive the Christian project as a selfish search for salvation which rejects the idea of serving others?" he asked.
While seeking to provide answers, the pope said there are ways for the faithful to learn and practice true Christian hope – in prayer, in suffering, in taking action and in looking at the Last Judgment as a symbol of hope.
"Only God can create justice. And faith gives us the certainty that He does so. The image of the Last Judgment is not primarily an image of terror, but an image of hope; for us it may even be the decisive image of hope. Is it not also a frightening image? I would say: it is an image that evokes responsibility, an image, therefore, of that fear of which Saint Hilary spoke when he said that all our fear has its place in love. God is justice and creates justice."
The first encyclical from Pope Benedict XVI was "God is Love," released last year. The third one is expected to be on "Faith," as it will complete the three Christian theological virtues – faith, hope and love.