“The days are long, but the years are short.”

Part of the secret "call and response" codewords by which members of the long-lived Howard Families can identify others:
: Life is short.
But the years are long.
Not while the evil days come not.
Methuselah's Children (1958)

Part 1, Ch. 13
Anne of Windy Poplars (1936)

On the knighthood of the rather short Sir Robert Muldoon in January 1984. Lange repeated the quote on U.S. television as an explanation of Sir Robert's dislike for him.
Source: Heinemann Dictionary of New Zealand Quotations (1988), p. 397.

"The Mariner's Cave", reported in Bartlett's Familiar Quotations, 10th ed. (1919).

This Business of Living (1935-1950)

Source: Short fiction, Dragonfield and Other Stories (1985), The Thirteenth Fey (p. 39)

Poems by Currer, Ellis, and Acton Bell (1846), To Cowper (1842)
Context: p>All for myself the sigh would swell,
The tear of anguish start;
I little knew what wilder woe
Had filled the Poet's heart.I did not know the nights of gloom,
The days of misery;
The long, long years of dark despair,
That crushed and tortured thee.</p

"Box of Rain"
Song lyrics, American Beauty (1970)

Second Week, Fourth Day, Book ii. Compare: " A life spent worthily should be measured by a nobler line,—by deeds, not years", Richard Brinsley Sheridan, Pizarro, Act iv, Scene 1.
La Seconde Semaine (1584)