Commonwealth member states are "guardians of a precious flame", the Queen will say in her Commonwealth Day radio message later.
She will also say that what the 53 nations share is more important now than at any point in its history.
The broadcast will have the theme of "A Young Commonwealth".
The Queen will also cite the success of last year's Commonwealth Games in Glasgow as an example of "youthfulness and vitality".
Queen's message hails 'precious flame' of Commonwealth
BBC News
9 March 2015
The Queen recorded her Commonwealth Day message in the Regency Room at Buckingham Palace
Commonwealth member states are "guardians of a precious flame", the Queen will say in her Commonwealth Day radio message later.
She will also say that what the 53 nations share is more important now than at any point in its history.
The broadcast will have the theme of "A Young Commonwealth".
The Queen will also cite the success of last year's Commonwealth Games in Glasgow as an example of "youthfulness and vitality".
The British Em..... sorry, the "Commonwealth"
She will say: "Not only are there tremendous rewards for this co-operation, but through dialogue we protect ourselves against the dangers that can so easily arise from a failure to talk or to see the other person's point of view.
"Indeed, it seems to me that now, in the second decade of the 21st Century, what we share through being members of the Commonwealth is more important and worthy of protection than perhaps at any other time in the Commonwealth's existence.
"We are guardians of a precious flame, and it is our duty not only to keep it burning brightly but to keep it replenished for the decades ahead."
'Unique in history'
She will also say that the shared history of the Commonwealth's members mean they can act on the "huge advantages of mutual co-operation and understanding" to benefit their citizens.
"As a concept that is unique in human history, the Commonwealth can only flourish if its ideas and ideals continue to be young and fresh and relevant to all generations," she will say.
The message will also be broadcast at Westminster Abbey, where the Queen will join 2,000 people, including senior royals and representatives from Commonwealth countries, for the annual Commonwealth Day service.
The Queen will be accompanied by the Duke of Edinburgh, the Prince of Wales and Duchess of Cornwall, and the Duke and Duchess of Cambridge.
Later, the Queen and Prince Philip will attend the traditional Commonwealth Day reception at Marlborough House, home of the Commonwealth Secretariat.
They will be there as guests of the Commonwealth Secretary-General, Kamalesh Sharma.
Commonwealth Secretary-General, Kamalesh Sharma
BBC News - Queen's message hails 'precious flame' of Commonwealth
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