Nothing, Lucilius, is ours, except time. We were entrusted by nature with the ownership of this single thing, so fleeting and slippery that anyone who will can oust us from possession. What fools these mortals be! They allow the cheapest and most useless things, which can easily be replaced, to be charged in the reckoning, after they have acquired them; but they never regard themselves as in debt when they have received some of that precious commodity, – time! And yet time is the one loan which even a grateful recipient cannot repay.
Seneca, Lucius Annaeus and Richard Mott Gummere (Translator). Moral Letters to Lucilius. 64 C.E.