Taoism

Tao Te King, chapter 6

The valley spirit dies not, aye the same;
The female mystery thus do we name.
Its gate, from which at first they issued forth,
Is called the root from which grew heaven and earth.
Long and unbroken does its power remain,
Used gently, and without the touch of pain.

Source Lao-tzu, Tâo Teh King, trans. James Legge, Sacred Books of the East vol. 39 (1891), en.wikisource.org · Contents