“I am skeptical about preventing wars. I doubt if they can be prevented. There will always be wars. Judging by past experiences, working for peace now would be as ineffective as ever. It's a law of nature.”

Broadcast (27 September 1938), quoted in The Times (28 September 1938), p. 10
Prime Minister

Address to Congress (1945)
Context: If wars in the future are to be prevented the nations must be united in their determination to keep the peace under law.
Nothing is more essential to the future peace of the world than continued cooperation of the nations which had to muster the force necessary to defeat the conspiracy of the Axis powers to dominate the world.
While these great states have a special responsibility to enforce the peace, their responsibility is based upon the obligations resting upon all states, large and small, not to use force in international relations except in the defense of law. The responsibility of the great states is to serve and not to dominate the world.

Letter to Guy Fleetwood Wilson (13 November 1936), quoted in Martin Gilbert, Prophet of Truth: Winston S. Churchill, 1922–1939 (London: Minerva, 1990), p. 800
The 1930s

A New Earth (2005)
Variant: Nothing ever happened in the past that can prevent you from being present now, and if the past cant prevent you from being present now, what power does it have?
Source: A New Earth: Awakening to Your Life's Purpose

Now is the Time to Prevent a Third World War (1950)
Context: World government must progressively be established, common problems must be solved by common action, economic and racial justice and fellowship must be achieved... empires must be transformed into commonwealths, the race of armaments must be stopped and the system of balance-of-armed-power must be brought to an end, the churches must take Jesus seriously by trusting goodwill and pacific means and by disentangling themselves from the war system, a mighty movement of peoples must be created so that governments will maintain friendly and cooperative relations and will refrain from hostile and provocative actions.... Now is the time to prevent a third world war.

What Does God Want Us to Do About Russia? (1948)

Letter in Harijan (1938) http://web.archive.org/20021008131454/die_meistersinger.tripod.com/gandhi9.html
1930s

Source: A Gift From Earth (1968), Ch. 10 : Parlette's Hand

As quoted in Peace Pilgrim: Her Life and Work in Her Own Words (1992) by Peace Pilgrim, p. 113.