“Who kindly sets a wand'rer on his way
Does e'en as if he lit another's lamp by his:
No less shines his, when he his friend's hath lit.”
As quoted by Cicero in De Officiis, Book I, Chapter XVI - translation by Walter Miller
Original
Homo qui erranti comiter monstrat viam, Quasi lumen de suo lumine accendat facit; Nihilo minus ipsi lucet, cum illi accenderit.
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Ennius 23
Roman writer -239–-169 BCRelated quotes

“He lit a lamp in broad daylight and said, as he went about, "I am looking for a human."”
Diogenes Laërtius, vi. 41. This line is frequently translated as "I am looking for an honest man."
Quoted by Diogenes Laërtius

1960s, The Drum Major Instinct (1968)

I, 1
The Persian Bayán

Source: 1940s, Resolving social conflicts; selected papers on group dynamics, 1948, p. 133 as cited in: Roger Dale, Madeleine MacDonald, Geoff Esland (1976) Schooling & Capitalism: A Sociological Reader. p. 111.
“He sets a thief to guard his purse
Who trusts a dial with his hours”
The Golden Ass (1999)
Context: He sets a thief to guard his purse
Who trusts a dial with his hours
Or bids a sand-glass bleed away his nights,
His days, his loves, his pleasures and his powers.
The burthen of his years
Is Time's soft footfall, Time's soft
Falling
Through his joys and tears.

The Golden Violet - The Eastern King
The Golden Violet (1827)