“This world, the whole of the planet called earth, is the common country of all who live and breathe upon it.”

Context: For four hundred years the human race has not made a step but what has left its plain vestige behind. We enter now upon great centuries. The sixteenth century will be known as the age of painters, the seventeenth will be termed the age of writers, the eighteenth the age of philosophers, the nineteenth the age of apostles and prophets. To satisfy the nineteenth century, it is necessary to be the painter of the sixteenth, the writer of the seventeenth, the philosopher of the eighteenth; and it is also necessary, like Louis Blane, to have the innate and holy love of humanity which constitutes an apostolate, and opens up a prophetic vista into the future. In the twentieth century war will be dead, the scaffold will be dead, animosity will be dead, royalty will be dead, and dogmas will be dead; but Man will live. For all there will be but one country—that country the whole earth; for all there will be but one hope—that hope the whole heaven.

Address to the Workman's Congress at Marseille http://en.wikisource.org/wiki/Victor_Hugo%27s_Address_to_the_Workman%27s_Congress_at_Marseille (1879)

VIII. 221–222 (tr. Samuel Butler).
Odyssey (c. 725 BC)

Source: Pebble in the Sky

1963, American University speech
Variant: For in the final analysis, our most basic common link, is that we all inhabit this small planet, we all breathe the same air, we all cherish our children's futures, and we are all mortal.
Source: Profiles in Courage
Context: In short, both the United States and its allies, and the Soviet Union and its allies, have a mutually deep interest in a just and genuine peace and in halting the arms race. Agreements to this end are in the interests of the Soviet Union as well as ours — and even the most hostile nations can be relied upon to accept and keep those treaty obligations, and only those treaty obligations, which are in their own interest. So, let us not be blind to our differences — but let us also direct attention to our common interests and to the means by which those differences can be resolved. And if we cannot end now our differences, at least we can help make the world safe for diversity. For, in the final analysis, our most basic common link is that we all inhabit this small planet. We all breathe the same air. We all cherish our children's future. And we are all mortal.

The Crisis No. IV.
1770s, The American Crisis (1776–1783)

Source: You Can Win: A Step by Step Tool for Top Achievers

Source: Drums, Girls & Dangerous Pie