“A thing of beauty is a joy forever:
Its loveliness increases; it will never
Pass into nothingness”

Source: Endymion: A Poetic Romance

Introductory poem.
Poems (1869)
Context: This is a haunted world. It hath no breeze
But is the echo of some voice beloved:
Its pines have human tones; its billows wear
The color and the sparkle of dear eyes.
Its flowers are sweet with touch of tender hands
That once clasped ours. All things are beautiful
Because of something lovelier than themselves,
Which breathes within them, and will never die. —
Haunted,—but not with any spectral gloom;
Earth is suffused, inhabited by heaven.

Source: A Streetcar Named Desire

Source: "A Shadow of the Night", p. 26 note: Unguarded Gates and Other Poems (1895)

Variant: Any moment might be our last. Everything is more beautiful because we're doomed. You will never be lovelier than you are now. We will never be here again.
Source: The Iliad

As quoted in Approaching God : How to Pray (1995) by Steve Brown, p. 94
Context: Spirituality means waking up. Most people, even though they don't know it, are asleep. They're born asleep, they live asleep, they marry in their sleep, they breed children in their sleep, they die in their sleep without ever waking up. They never understand the loveliness and the beauty of this thing that we call human existence. You know — all mystics — Catholic, Christian, non-Christian, no matter what their theology, no matter what their religion — are unanimous on one thing: that all is well, all is well. Though everything is a mess, all is well. Strange paradox, to be sure. But, tragically, most people never get to see that all is well because they are asleep. They are having a nightmare.

The Complete Neurotic's Notebook (1981), Love