Tao Te Ching · Chapter 46

天下有道，卻走馬以糞。
天下無道，戎馬生於郊。
禍莫大於不知足；咎莫大於欲得。故知足之足，常足矣。

When the Tao prevails in the world, they send back their swift
horses to (draw) the dung-carts. When the Tao is disregarded in the
world, the war-horses breed in the border lands.

There is no guilt greater than to sanction ambition; no calamity
greater than to be discontented with one's lot; no fault greater than
the wish to be getting. Therefore the sufficiency of contentment is
an enduring and unchanging sufficiency.