Tao Te Ching: Chapter 30
He who would assist a lord of men in harmony with the Tao will not assert his mastery in the kingdom by force of arms. Such a course is sure to meet with its proper return.
Wherever a host is stationed, briars and thorns spring up. In the sequence of great armies there are sure to be bad years.
A skilful (commander) strikes a decisive blow, and stops. He does not dare (by continuing his operations) to assert and complete his mastery. He will strike the blow, but will be on his guard against being vain or boastful or arrogant in consequence of it. He strikes it as a matter of necessity; he strikes it, but not from a wish for mastery.
When things have attained their strong maturity they become old. This may be said to be not in accordance with the Tao: and what is not in accordance with it soon comes to an end.