Letters 93.2

But tell me, pray, do you consider it fairer that you should obey Nature, or that Nature should obey you? And what difference does it make how soon you depart from a place which you must depart from sooner or later? We should strive, not to live long, but to live rightly; for to achieve long life you have need of Fate only, but for right living you need the soul. A life is really long if it is a full life; but fulness is not attained until the soul has rendered to itself its proper Good, that is, until it has assumed control over itself.

Seneca, Letters to Lucilius 93.2, translated by Richard Mott Gummere