不闻不若闻之, 闻之不若见之, 见之不若知之, 知之不若行之

Not having heard something is not as good as having heard it;

having heard it is not as good as having seen it;

having seen it is not as good as knowing it;

knowing it is not as good as putting it into practice.

Xunzi, of Xun Kuang (3rd C BCE) compiled by Liu Xiang. Ch.11: Bk.8: Ruxiao ("The Teachings of the Ru") 9th C CE. Translated by John Knoblock