“Some must be warriors, that others may live in peace.”

Source: The Wheel of Time: Shamans of Ancient Mexico, Their Thoughts About Life, Death and the Universe], (1998), Quotations from A Separate Reality (Chapter 6)

Original: Per vivere in pace, bisogna sempre fregarsene di ciò che pensano gli altri.
Source: prevale.net

Go Rin No Sho (1645), The Book No-Thing-ness
Context: To attain the Way of strategy as a warrior you must study fully other martial arts and not deviate even a little from the Way of the warrior. With your spirit settled, accumulate practice day by day, and hour by hour. Polish the twofold spirit heart and mind, and sharpen the twofold gaze perception and sight. When your spirit is not in the least clouded, when the clouds of bewilderment clear away, there is the true void.

1930s, Quarantine Speech (1937)
Context: If civilization is to survive, the principles of the Prince of Peace must be restored. Shattered trust between nations must be revived. Most important of all, the will for peace on the part of peace-loving nations must express itself to the end that nations that may be tempted to violate their agreements and the rights of others will desist from such a cause. There must be positive endeavors to preserve peace. America hates war. America hopes for peace. Therefore, America actively engages in the search for peace.

The Art of Peace (1992)
Context: When life is victorious, there is birth; when it is thwarted, there is death. A warrior is always engaged in a life-and-death struggle for Peace.

1930s, Quarantine Speech (1937)
Context: Those who cherish their freedom and recognize and respect the equal right of their neighbors to be free and live in peace must work together for the triumph of law and moral principles in order that peace, justice, and confidence may prevail in the world. There must be a return to a belief in the pledged word, in the value of a signed treaty. There must be recognition of the fact that national morality is as vital as private morality.

"La vida es difícil. Para estar en paz con uno mismo hay que decir la verdad. Para estar en paz con el prójimo hay que mentir."
Descanso de caminantes, 2001.

Speaking of a vision of the "Great Spirit of Peace" in 1942, during World War II, as quoted in Adjusting Though Reflex : Romancing Zen (2010) by Rodger Hyodo, p. 76
Context: The Way of the Warrior has been misunderstood. It is not a means to kill and destroy others. Those who seek to compete and better one another are making a terrible mistake. To smash, injure, or destroy is the worst thing a human being can do. The real Way of a Warrior is to prevent such slaughter — it is the Art of Peace, the power of love.