Tao produces unity; unity produces duality; duality produces trinity; trinity produces all things. All things bear the negative principle (yin) and embrace the positive principle (yang). Immaterial vitality, the third principle (chi), makes them harmonious.
Those things which are detested by the common people, namely to be called orphans, inferiors, and unworthies, are the very things kings and lords take for titles. There are some things which it is a gain to lose, and a loss to gain.
I am teaching the same things which are taught by others. But the strong and aggressive: ones do not obtain a natural death (i.e., self-confident teachers do not succeed). I alone expound the basis of the doctrine of the Tao.
~ Tao Te Ching, Chapter 42
(Dwight Goddard and Henri Borel, , via sacred-texts.com)