Persevere

[H]owever close we sometimes seem to that dark and final abyss, let no man of peace and freedom despair. For he does not stand alone. If we all can persevere, if we can in every land and office look beyond our own shores and ambitions, then surely the age will dawn in which the strong are just and the weak secure and the peace preserved.

...Never have the nations of the world had so much to lose, or so much to gain. Together we shall save our planet, or together we shall perish in its flames. Save it we can--and save it we must--and then shall we earn the eternal thanks of mankind and, as peacemakers, the eternal blessing of God.

--John F. Kennedy, Address to the UN General Assembly, September 25, 1961