Tao Te Ching · Ch. 52

天下有始,以為天下母。既得其母,以知其子;既知其子,復守其母,沒身不殆。塞其兌,閉其門,終身不勤。開其兌,濟其事,終身不救。見小曰明,守柔曰強。用其光,復歸其明,無遺身殃;是為習常。

Tiān xià yǒu shǐ, yǐ wéi tiān xià mǔ. Jì dé qí mǔ, yǐ zhī qí zǐ; Jì zhī qí zǐ, fù shǒu qí mǔ, mò shēn bù dài. Sāi qí duì, bì qí mén, zhōng shēn bù qín. Kāi qí duì, jì qí shì, zhōng shēn bù jiù. Jiàn xiǎo yuē míng, shǒu róu yuē qiáng. Yòng qí guāng, fù guī qí míng, wú yí shēn yāng; Shì wéi xí cháng.

The world had a beginning, and that beginning is the world's mother. Having found the mother, one knows the children; knowing the children, return to the mother — and until the end of life there is no danger. Block the openings, close the gates, and to the end of life there is no exhaustion. Open the openings, busy oneself with affairs, and to the end of life there is no rescue. To perceive the small is called clarity; to hold to softness is called strength. Use the light to return to clarity; bring no calamity upon yourself — this is called practicing the constant.

— Tao Te Ching 52

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