Think of our world as it looks from that rocket that is heading toward Mars. It is like a child’s globe, hanging in space, the continents stuck to its side like colored maps. We are all fellow passengers on a dot of earth. And each of us, in the span of time, has really only a moment among our companions.
How incredible it is that in this fragile existence we should hate and destroy one another. There are possibilities enough for all who will abandon mastery over others to pursue mastery over nature. There is world enough for all to seek their happiness in their own way.

Lyndon B. Johnson (1908-1973) American politician, educator, US President (1963-69)

Speech (1965-01-20), Inaugural Address, Washington, D. C.
    (Source)

This is in the formal text of the speech, delivered at the US Capitol building, but a review of the videos (1, 2, 3) shows this as part of a large section of the speech he skipped (from the end of the "AMERICAN COVENANT" section directly to the "AMERICAN BELIEF" section).