Marcus Aurelius, Meditations
Even if you’re going to live three thousand more years, or ten times that, remember, you cannot lose another life than the one you’re living now, or live another one than the one you’re losing. The longest amounts to the shortest. The present is the same for everyone; its loss is the same for everyone; and it should be clear that a brief instant is all that is lost. For you can’t lose either the past or the future; how could you lose what you don’t have?
Remember two things:
i - that everything has always been the same, and keeps recurring, and it makes no difference whether you see the same things recur in a hundred years or two hundred, or in an infinite period;
ii - that the longest-lived and those who will die soonest lose the same thing. The present is all that they can give up, since that is all you have, and what you do not have, you cannot lose.