“You spend your whole life grieving for those who haven’t died yet.”

Source: The Clowns of God (1981), Ch. II (ellipses in original) <!-- p. 35 -->
This statement begins with a quotation from Horace, Odes, Book I, Ode ix, line 13.
Context: "Forbear to ask what tomorrow may bring" … If you spend your whole life waiting for the storm, you'll never enjoy the sunshine.

Source: Invisible Monsters

Variant: Zero wasnt worried, " When you spend your whole life living in a shole", he said, "the only way you can go is up.
Source: Holes

"Light" (popularly known as "The Night has a Thousand Eyes"), published in The Spectator (October 1873).
Context: p>The Night has a thousand eyes,
And the Day but one;
Yet the light of the bright world dies
With the dying sun.The mind has a thousand eyes,
And the heart but one;
Yet the light of a whole life dies
When love is done.</p

Tsurezure-Gusa (Essays in Idleness)

Source: I. Asimov: A Memoir (1994), p. 538

Source: Five Finger Exercise