If thou shouldst live three thousand, or as many as ten thousands of years, yet remember this, that man can part with no life properly, save with that little part of life, which he now lives: and that which he lives, is no other, than that which at every instant he parts with.
 Marcus Aurelius, Meditations (c. 170 - 180). copy citation

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Author Marcus Aurelius
Source Meditations
Topic instant life
Date c. 170 - 180
Language English
Reference
Note Translated by Meric Casaubon
Weblink https://en.wikisource.org/wiki/Marcus_Aurelius_Antoninus_-_His_Meditatio...

Context

“For indeed whatsoever proceeds from the gods, deserves respect for their worth and excellency; and whatsoever proceeds from men, as they are our kinsmen, should by us be entertained, with love, always; sometimes, as proceeding from their ignorance, of that which is truly good and bad, (a blindness no less, than that by which we are not able to discern between white and black:) with a kind of pity and compassion also.
XII. If thou shouldst live three thousand, or as many as ten thousands of years, yet remember this, that man can part with no life properly, save with that little part of life, which he now lives: and that which he lives, is no other, than that which at every instant he parts with. That then which is longest of duration, and that which is shortest, come both to one effect. For although in regard of that which is already past there may be some inequality, yet that time which is now present and in being, is equal unto all men.” source