Queen Elizabeth II used her televised Christmas speech to praise the virtues of religious and ethnic tolerance, telling the Commonwealth that diversity is "a strength and not a threat".
And in a separate special message to her country's troops serving around the world, notably in Iraq, she also expressed pride in their work and support at the end of a "very demanding year."
"Religion and culture are much in the news these days, usually as sources of difference and conflict, rather than for bringing people together. But the irony is that every religion has something to say about tolerance and respecting others," the 78-year-old monarch said in her annual address to the Commonwealth, as she reflected on the meaning of Christmas.
"For me, as a Christian, one of the most important of these teachings is contained in the parable of the Good Samaritan, when Jesus answers the question, 'Who is my neighbour?,'" she said.
"It is a timeless story of a victim of a mugging who was ignored by his own countrymen but helped by a foreigner -- and a despised foreigner at that. The implication drawn by Jesus is clear. Everyone is our neighbour, no matter what race, creed or colour. The need to look after a fellow human being is far more important than any cultural or religious differences."
The queen went on to highlight the benefits of diversity, noting that "we have only to look around to recognise the benefits of this positive approach in business or local government, in sport, music and the arts."
While conceding that many challenges lie ahead she sounded an upbeat note about the future in a globalised world.
"There is certainly much more to be done and many challenges to be overcome. Discrimination still exists. Some people feel that their own beliefs are being threatened. Some are unhappy about unfamiliar cultures," she said.
"They all need to be reassured that there is so much to be gained by reaching out to others; that diversity is indeed a strength and not a threat. We need also to realise that peaceful and steady progress in our society of differing cultures and heritage can be threatened at any moment by the actions of extremists at home or by events abroad. We can certainly never be complacent.
"But there is every reason to be hopeful about the future. ... I believe tolerance and fair play remain strong British values and we have so much to build on for the future," the queen said.
Religious leaders praised the sovereign's speech.
Iqbal Sacranie, secretary general of the Muslim Council of Britain, called it "very timely" and a positive message that would "help promote understanding and social cohesion".
Jonathan Romain, a rabbi from the Reform Synagogues of Great Britain, said it was "exactly the right message for 2005".
The speech was interspersed with video sequences including one shot in an Islamic centre in which she appears with her head and shoulders covered by a scarf.
The monarch also recounted an anecdote she heard from an overseas visitor who said the best part of his visit had been "traveling from Heathrow into central London on the Tube.
"His British friends were, as you can imagine, somewhat surprised, particularly as the visitor had been to some of the great attractions of the country. What do you mean, they asked?," the queen said.
"Because, he replied, I boarded the train just as the schools were coming out. At each stop children were getting on and off -- they were of every ethnic and religious background, some with scarves or turbans, some talking quietly, others playing and occasionally misbehaving together -- completely at ease and trusting one another. How lucky you are, said the visitor, to live in a country where your children can grow up this way."
In her separate message to the troops, the queen said: "I would like to send a special message to all of you in the services spending Christmas on active duty away from home.
"It has been a very demanding year. I am proud of the way that you have risen to the challenges with typical professionalism," she added.
It was the first time the queen had broadcast such a message in all the 52 years of her reign. It came as British troops have been facing growing violence in Iraq.
"The conflict in Iraq has dominated the headlines at home, but I am only too aware that whilst many of you have been deployed there, others have been working tirelessly in many other theatres," the queen said.
"Wherever you are, I would like to express my gratitude for your service this year, and I send each and every one of you my good wishes for Christmas and the New Year," she said.