. . . Ah, happy, happy boughs! that cannot shed
Your leaves, nor ever bid the Spring adieu;
And, happy melodist, unwearied,
For ever piping songs for ever new;
More happy love! more happy, happy love!
For ever warm and still to be enjoy’d,
For ever panting, and for ever young;
All breathing human passion far above,
That leaves a heart high-sorrowful and cloy’d,
A burning forehead, and a parching tongue.
Who are these coming to the sacrifice?
To what green altar, O mysterious priest,
Lead’st thou that heifer lowing at the skies,
And all her silken flanks with garlands drest?
What little town by river or sea shore,
Or mountain-built with peaceful citadel,
Is emptied of this folk, this pious morn?
And, little town, thy streets for evermore
Will silent be; and not a soul to tell
Why thou art desolate, can e’er return. . . .
"Ode on a Grecian Urn" - it's short, you can read it in its entirety here: Ode on a Grecian Urn
I have never read anything else so eloquent on the chasm between time and eternity.