The master once said: The generation of all men and of all things in the universe is accomplished by means of the marvelous interaction of the two forces [yin and yang]. Man is the most highly endowed of all creatures, and all things culminate in man. Generation after generation men have taken their livelihood from tilling the soil, or devised and manufactured tools, or produced profit from mutual trade, so that peoples' needs were satisfied. Thus the occupations of farmer, artisan, and merchant necessarily grew up as complementary to one another. However, the samurai eats food without growing it, uses utensils without manufacturing them, and profits without buying or selling. What is the justification for this? When I reflect today on my pursuit in life [I realize that] I was born into a family whose ancestors for generations have been warriors, and whose pursuit is service at court. The samurai is one who does not cultivate, does not manufacture, and does not engage in trade, but it cannot be that he has no function at all as a samurai. He who satisfied his needs without performing any function at all would more properly be called an idler. Therefore one must devote all one's mind to the detailed examination of one's calling