Tao Te Ching · Chapter 43

天下之至柔，馳騁天下之至堅。
無有入無間，吾是以知無為之有益。
不言之教，無為之益，天下希及之。

The softest thing in the world dashes against and overcomes the
hardest; that which has no (substantial) existence enters where there
is no crevice. I know hereby what advantage belongs to doing nothing
(with a purpose).

There are few in the world who attain to the teaching without
words, and the advantage arising from non-action.