Zenit reports that the pontiff issued the warning on Monday in a meeting with Cardinal Friedrich Wetter, retired archbishop of Munich, who was accompanied by 50 delegates for Benedict's 80th birthday celebrations.
Cardinal Wetter succeeded then Cardinal Joseph Ratzinger, who led the archdiocese from 1977 to 1982.
The Holy Father told them briefly about the audience he had just had with Edmund Stoiber, minister-president of the Pope's native Bavaria, and Peter Harry Carstensen, minister-president of Schleswig-Holstein.
The Pontiff said: "Despite the environments from which the two come, and their notably different temperaments, both of them showed an interior certainty that the faith opens a future, and that in this moment of encounter between cultures, as well as in the impending clash between them, it is highly important that the interior, peaceful and renewing strength of the Christian faith stays alive in our culture, thereby acting as a positive influence on the future."
Meanwhile, Australia's Catholic bishops have invited Christians, Muslims and Jews to meet together and discuss "The Role of Religion in Achieving Peace in the Middle East".
In a statement, the Australian Catholic Bishops Conference says it will bring together key people from the Christian, Muslim and Jewish religious traditions for two "groundbreaking events focusing on understanding and achieving Peace in the Middle East."
The first event, chaired by the bishops' Commission for Ecumenism and Inter-religious Relations chairman, Bishop Michael Putney, is a day-long congress to be held at NSW Parliament House on Wednesday, 2 May.
The congress will be followed by a public event on 3 May at Notre Dame University of Australia's Broadway campus, chaired by NSW Governor Professor Marie Bashir.
Both the Parliament House Congress and the public event will be significant events in Australian interreligious affairs, the statement said.
Speakers on both occasions will be Mr Mohommad Sammak, Archbishop Elias Chacour and Mr Jeremy Jones.
Mr Sammak is the Secretary-General of the Lebanese Christian-Muslim Committee for Dialogue and Secretary General of the Islamic Spiritual Council in Lebanon. Archbishop Chacour is the Melkite Catholic Archbishop of Akka, Haifa, Nazareth and all Galilee. Mr Jones is the Director of International and Community Affairs for Australia/Israel & Jewish Affairs Council.
"The Australian Bishops initiated these events as means of gathering together leaders and experts from Christianity, Islam and Judaism to consider the complex question of 'The Role of Religion in Achieving Peace in the Middle East'," bishops conference president Archbishop Philip Wilson said.
"Obviously this is a huge question, but we are confident that in listening to the wisdom of each speaker we can make at least some small progress towards understanding, which is the first step towards progress."
Christian Peace Could Avert "the Clash" (Zenit, 18/4/07)
Catholic Bishops invite Christians, Muslims and Jews to meet together and discuss The Role of Religion in Achieving Peace in the Middle East (ACBC Media Release, 18/4/07)
Mohammad Sammak on role of Arab Christians to help bridge gulf dividing world religions (US Presbyterian Church News Service, 6/9/05)
LINKS (not necessarily endorsed by Church Resources)
Australian Catholic Bishops Conference
The Holy See
Cardinal Friedrich wetter (Wikipedia)
Edmund Stoiber (Wikipedia)
Peter Harry Carstensen (Wikipedia)
Clash of Civilizations (Wikipedia)
UN chief warns against new religion world war (CathNews, 21/9/06)
Human Rights Watch writes to Pope Benedict XVI on the situation in Sri Lanka (Tamil Brisbane, 18/4/07)
19 Apr 2007