From
韩愈《
马说》(Han Yu, Tang, ~800 CE), a short allegorical essay:
世有伯乐,
然后有千里马。
千里马常有,
而伯乐不常有。
故虽有名马,
祗辱于奴隶人之手,
骈死于槽枥之间 (The world must first have a Bole, and then there can be a thousand-li horse. Thousand-li horses are common; a Bole is not. So though a famous horse exists, it is shamed at the hands of grooms, and dies side by side in the stalls).
伯乐 = the legendary Qin-era horse-judge; a classic meditation on talent going unrecognized.