“True Budo is done for the sake of "building peace". Train every day so as to make peace between this spirit [Budo] and all things manifested on the face of the Earth.”

The Art of Peace (1992)
Context: In order to establish heaven on earth, we need a Budo that is pure in spirit, that is devoid of hatred and greed. It must follow natural principles and harmonize the material with the spiritual. Aikido means not to kill. Although nearly all creeds have a commandment against taking life, most of them justify killing for reason or another. In Aikido, however, we try to completely avoid killing, even the most evil person.

Source: Budo Training in Aikido (1933), p. 26

On Marriage (1530)

Letter to John Jay (15 August 1786) http://gwpapers.virginia.edu/documents/constitution/1784/jay2.html
1780s
Context: If you tell the Legislatures they have violated the treaty of peace and invaded the prerogatives of the confederacy they will laugh in your face. What then is to be done? Things cannot go on in the same train forever. It is much to be feared, as you observe, that the better kind of people being disgusted with the circumstances will have their minds prepared for any revolution whatever. We are apt to run from one extreme into another. To anticipate & prevent disasterous contingencies would be the part of wisdom & patriotism.
What astonishing changes a few years are capable of producing! I am told that even respectable characters speak of a monarchical form of government without horror. From thinking proceeds speaking, thence to acting is often but a single step. But how irrevocable & tremendous! What a triumph for the advocates of despotism to find that we are incapable of governing ourselves, and that systems founded on the basis of equal liberty are merely ideal & falacious! Would to God that wise measures may be taken in time to avert the consequences we have but too much reason to apprehend.
Retired as I am from the world, I frankly acknowledge I cannot feel myself an unconcerned spectator. Yet having happily assisted in bringing the ship into port & having been fairly discharged; it is not my business to embark again on a sea of troubles. Nor could it be expected that my sentiments and opinions would have much weight on the minds of my Countrymen — they have been neglected, tho' given as a last legacy in the most solemn manner. I had then perhaps some claims to public attention. I consider myself as having none at present.

The Columbia River Collection (1941), Biggest Thing That Man Has Ever Done
Variant: The world is digging, slavery's grave and when the job is done
This'll be the biggest thing that man has ever done.
Context: I'd better quit my talking, 'cause I told you all I know,
But please remember, pardner, wherever you may go,
The people are building a peaceful world, and when the job is done
That'll be the biggest thing that man has ever done.

1963, American University speech
Context: I have, therefore, chosen this time and this place to discuss a topic on which ignorance too often abounds and the truth is too rarely perceived — yet it is the most important topic on earth: world peace. What kind of peace do I mean? What kind of peace do we seek? Not a Pax Americana enforced on the world by American weapons of war. Not the peace of the grave or the security of the slave. I am talking about genuine peace, the kind of peace that makes life on earth worth living, the kind that enables men and nations to grow and to hope and to build a better life for their children — not merely peace for Americans but peace for all men and women — not merely peace in our time but peace for all time.

Peace Train
Song lyrics, Teaser and the Firecat (1971)

2000s, 2004, Speech to United Nations General Assembly (September 2004)