Nature's gift. Seneca, Epistulae 1.1.3
According to Seneca, Nature's special gift to humanity is time. This passage reminds me of Buddhist teachings about 'precious human existence' (मनुष्यगति, manusyagati). You can hear me read it <here>.
Dum differtur vita transcurrit. Omnia, Lucili, aliena sunt, tempus tantum nostrum est; in huius rei unius fugacis ac lubricae possessionem natura nos misit, ex qua expellit quicumque vult. Et tanta stultitia mortalium est ut quae minima et vilissima sunt, certe reparabilia, imputari sibi cum impetravere patiantur, nemo se iudicet quicquam debere qui tempus accepit, cum interim hoc unum est quod ne gratus quidem potest reddere.
Life runs past us, while we waste time. All things, Lucilius, are foreign to us; only time is truly ours. Nature sent us forth to possess this one thing, fleeting and slippery as it is, from which she drives anyone who really wants it. And such is the stupidity of mortals that they allow themselves to become liable for the meanest and paltriest possessions, things that anyone might easily repair, but nobody who has taken time from another even thinks he owes a debt, though this is the one thing he cannot ever freely return.