Tao Te Ching · Ch. 70

吾言甚易知,甚易行。天下莫能知,莫能行。言有宗,事有君。夫唯無知,是以不我知。知我者希,則我者貴。是以聖人被褐懷玉。

Wú yán shèn yì zhī, shèn yì xíng. Tiān xià mò néng zhī, mò néng xíng. Yán yǒu zōng, shì yǒu jūn. Fú wéi wú zhī, shì yǐ bù wǒ zhī. Zhī wǒ zhě xī, zé wǒ zhě guì. Shì yǐ shèng rén bèi hè huái yù.

My words are very easy to know and very easy to practice. Yet no one under heaven is able to know them, and no one is able to practice them. My words have an ancestor; my actions have a lord. Because people do not understand this, they do not understand me. Those who understand me are few; those who act on my understanding are precious. Therefore the sage wears coarse cloth on the outside but carries jade within.

— Tao Te Ching 70

Source: Wang Bi edition (Chinese) + Hanyu Pinyin transliteration