“Human has always striven to retain the past, to keep it convincing; there's nothing wicked in that. Without it we have no continuity; we have only the moment. And, deprived of the past, the moment - the present - has little meaning, if any.”

Source: Meditations

As quoted in "The Gentle Philosopher" (2006) by John Little at the Will Durant Foundation https://web.archive.org/web/20130312115951/http://www.willdurant.com/home.html
Context: It is a mistake to think that the past is dead. Nothing that has ever happened is quite without influence at this moment. The present is merely the past rolled up and concentrated in this second of time. You, too, are your past; often your face is your autobiography; you are what you are because of what you have been; because of your heredity stretching back into forgotten generations; because of every element of environment that has affected you, every man or woman that has met you, every book that you have read, every experience that you have had; all these are accumulated in your memory, your body, your character, your soul. So with a city, a country, and a race; it is its past, and cannot be understood without it.

Billy writing a letter to a newspaper describing the Tralfamadorians
Slaughterhouse-Five (1969)
Context: The most important thing I learned on Tralfamadore was that when a person dies he only appears to die. He is still very much alive in the past, so it is very silly for people to cry at his funeral. All moments, past, present and future, always have existed, always will exist. The Tralfamadorians can look at all the different moments just that way we can look at a stretch of the Rocky Mountains, for instance. They can see how permanent all the moments are, and they can look at any moment that interests them. It is just an illusion we have here on Earth that one moment follows another one, like beads on a string, and that once a moment is gone it is gone forever.
When a Tralfamadorian sees a corpse, all he thinks is that the dead person is in bad condition in the particular moment, but that the same person is just fine in plenty of other moments. Now, when I myself hear that somebody is dead, I simply shrug and say what the Tralfamadorians say about dead people, which is "So it goes."

Aleph (2011)

Original: (it) Il passato ha concluso il suo tempo, il presente è l'attimo, il futuro il divenire.
Source: prevale.net

Understanding Our Mind (2006) Parallax Press ISBN 978-81-7223-796-7

1870s, Society and Solitude (1870), Quotation and Originality
Context: We cannot overstate our debt to the Past, but the moment has the supreme claim. The Past is for us; but the sole terms on which it can become ours are its subordination to the Present. Only an inventor knows how to borrow, and every man is or should be an inventor. We must not tamper with the organic motion of the soul.

Source: Stay