Dēng bù diǎn, bù liàng; (lǐ bù shuō, bùmíng).

燈不點不亮, (理不說不明)。

Lit [Just as] a lamp won't be bright until it is lit, ([so people will] not understand unless reason has been explained).

Note [The first part is commonly used alone, with the second part left unsaid, like a xiehouyu; see also the following entry.]

Topics enigmatic folk simile EXPLANATIONS REASON UNDERSTANDING xiehouyu