“Mankind must put an end to war - or war will put an end to mankind.”

1961, UN speech
Context: Mankind must put an end to war — or war will put an end to mankind.
So let us here resolve that Dag Hammarskjold did not live, or die, in vain. Let us call a truce to terror. Let us invoke the blessings of peace. And as we build an international capacity to keep peace, let us join in dismantling the national capacity to wage war.
Context: We meet in an hour of grief and challenge. Dag Hammarskjold is dead. But the United Nations lives. His tragedy is deep in our hearts, but the task for which he died is at the top of our agenda. A noble servant of peace is gone. But the quest for peace lies before us.
The problem is not the death of one man — the problem is the life of this organization. It will either grow to meet the challenges of our age, or it will be gone with the wind, without influence, without force, without respect. Were we to let it die, to enfeeble its vigor, to cripple its powers, we would condemn our future. For in the development of this organization rests the only true alternative to war — and war appeals no longer as a rational alternative. Unconditional war can no longer lead to unconditional victory. It can no longer serve to settle disputes. It can no longer concern the great powers alone. For a nuclear disaster, spread by wind and water and fear, could well engulf the great and the small, the rich and the poor, the committed and the uncommitted alike. Mankind must put an end to war — or war will put an end to mankind.
So let us here resolve that Dag Hammarskjold did not live, or die, in vain. Let us call a truce to terror. Let us invoke the blessings of peace. And as we build an international capacity to keep peace, let us join in dismantling the national capacity to wage war.