“Although all things are not to be judged in this manner, I mention it in the investigation of the Way of the Samurai. When the time comes, there is no moment for reasoning. And if you have not done your inquiring beforehand, there is most often shame.”

Variant: You will find, as you look back upon your life, that the moments when you really lived are the moments when you have done things in the spirit of love.

March 18, 2016, Merrick Garland, Presentation of the Friendly Medal to William H. Webster, May 24, 2013, American Law Institute https://www.youtube.com/watch?v=A5U6ekOfpi4, and also excerpted quote in:
[March 18, 2016, The Quotable Merrick Garland: A Collection of Writings and Remarks, http://www.nationallawjournal.com/home/id=1202752327128/The-Quotable-Merrick-Garland-A-Collection-of-Writings-and-Remarks, Zoe Tillman, The National Law Journal, March 16, 2016, 0162-7325]
Court opinions and media comments

Quoted in: Honor Books, ‎W. B. Freeman (2004), God's Little Devotional Book for Girls, p. 205
2000s

Mesillat Yesharim (1738), Chapter 6

Quoted in Charlie Chaplin, My Autobiography (1964)

Richard Friedenthal, (1963, p. 260).
1930s, "Conversations avec Picasso," 1934–35

Source: Plan B: Further Thoughts on Faith

As translated by William Scott Wilson. This first sentence of this passage was used as a military slogan during the early 20th century to encourage soldiers to throw themselves into battle. Variant translations:
Bushido is realised in the presence of death. In the case of having to choose between life and death you should choose death. There is no other reasoning. Move on with determination. To say dying without attaining ones aim is a foolish sacrifice of life is the flippant attitude of the sophisticates in the Kamigata area. In such a case it is difficult to make the right judgement. No one longs for death. We can speculate on whatever we like. But if we live without having attaining that aim, we are cowards. This is an important point and the correct path of the Samurai. When we calmly think of death morning and evening and are in despair, We are able to gain freedom in the way of the Samurai. Only then can we fulfil our duty without making mistakes in life.
By the Way of the warrior is meant death. The Way of the warrior is death. This means choosing death whenever there is a choice between life and death. It means nothing more than this. It means to see things through, being resolved.
I have found that the Way of the samurai is death. This means that when you are compelled to choose between life and death, you must quickly choose death.
The way of the Samurai is in death.
I have found the essence of Bushido: to die!
Hagakure (c. 1716)
Context: The Way of the Samurai is found in death. When it comes to either/or, there is only the quick choice of death. It is not particularly difficult. Be determined and advance. To say that dying without reaching one's aim is to die a dog's death is the frivolous way of sophisticates. When pressed with the choice of life or death, it is not necessary to gain one's aim.
We all want to live. And in large part we make our logic according to what we like. But not having attained our aim and continuing to live is cowardice. This is a thin dangerous line. To die without gaining one's aim is a dog's death and fanaticism. But there is no shame in this. This is the substance of the Way of the Samurai. If by setting one's heart right every morning and evening, one is able to live as though his body were already dead, he gains freedom in the Way. His whole life will be without blame, and he will succeed in his calling.