Taoist Sacred Texts. Vol.I. 

When wood is rubbed against wood, it begins to burn; when metal is subjected to fire, it (melts and) flows. When the Yin and Yang act awry, heaven and earth are greatly perturbed; and on this comes the crash of thunder, and from the rain comes fire, which consumes great locust trees.

The case of men is still worse. They are troubled between two pitfalls, from which they cannot escape. Chrysalis-like, they can accomplish nothing. Their minds are as if hung up between heaven and earth. Now comforted, now pitied, they are plunged in difficulties. The ideas of profit and of injury rub against each other, and produce in them a very great fire. The harmony (of the mind) is consumed in the mass of men. Their moonlike intelligence cannot overcome the (inward) fire. They thereupon fall away more and more, and the Course (which they should pursue) is altogether lost.