“I declare before you all that my whole life whether it be long or short shall be devoted to your service and the service of our great imperial family to which we all belong.”

As quoted in The Life Of Lord Courtney (1920) by G. P. Gooch
The statement "The price of peace is eternal vigilance" has been widely attributed to others, including George Marshall, however even Courtney's use of it is probably derived from an earlier statement with several variants:
The price of freedom is eternal vigilance.
The price of liberty is eternal vigilance.
Eternal vigilance is the price of liberty.

2018, Nelson Mandela Annual Lecture (2018)
Context: It was in service of this long walk towards freedom and justice and equal opportunity that Nelson Mandela devoted his life. At the outset, his struggle was particular to this place, to his homeland – a fight to end apartheid, a fight to ensure lasting political and social and economic equality for its disenfranchised non-white citizens. But through his sacrifice and unwavering leadership and, perhaps most of all, through his moral example, Mandela and the movement he led would come to signify something larger. He came to embody the universal aspirations of dispossessed people all around the world, their hopes for a better life, the possibility of a moral transformation in the conduct of human affairs.
Madiba’s light shone so brightly, even from that narrow Robben Island cell, that in the late ‘70s he could inspire a young college student on the other side of the world to reexamine his own priorities, could make me consider the small role I might play in bending the arc of the world towards justice. And when later, as a law student, I witnessed Madiba emerge from prison, just a few months, you’ll recall, after the fall of the Berlin Wall, I felt the same wave of hope that washed through hearts all around the world.
Do you remember that feeling? It seemed as if the forces of progress were on the march, that they were inexorable. Each step he took, you felt this is the moment when the old structures of violence and repression and ancient hatreds that had so long stunted people’s lives and confined the human spirit – that all that was crumbling before our eyes. And then, as Madiba guided this nation through negotiation painstakingly, reconciliation, its first fair and free elections; as we all witnessed the grace and the generosity with which he embraced former enemies, the wisdom for him to step away from power once he felt his job was complete, we understood that – we understood it was not just the subjugated, the oppressed who were being freed from the shackles of the past. The subjugator was being offered a gift, being given a chance to see in a new way, being given a chance to participate in the work of building a better world.

Source: The Sayings and Teachings of the Great Mystics of Islam (2004), p. 270

Letter to Tommaso dei Cavalieri (1 January 1533).

Fourteen Points https://www.marxists.org/archive/mcmanus/articles/points.htm, Halifax Division of the Socialist Labour Party, (1918)

Source: Karaoke Capitalism, 2005, p. 224

Source: Karaoke Capitalism, 2005, p. 224

Source: Books, Spiritual Warrior, Volume III: Solace for the Heart in Difficult Times (Hari-Nama Press, 2000), Chapter 8 - How To Strengthen Ourselves