[FN#169] The expression first occurs in Ho-bo-dan-kyo of the Sixth Patriarch, and is frequently used by later Zenists.

13.  The Theory of Buddha-Nature adequately explains the Ethical States of Man.

This theory of Buddha-nature enables us to get an insight into the origin of morality.  The first awakening of Buddha-nature within man is the very beginning of morality, and man’s ethical progress is the gradually widening expression of that nature in conduct.  But for it morality is impossible for man.  But for it not only moral culture or discipline, but education and social improvement must be futile.  Again, the theory adequately explains the ethical facts that the standard of morality undergoes change in different times and places, that good and bad are so inseparably knit together, and that the bad at times become good all on a sudden, and the good grow bad quite unexpectedly.  First, it goes without saying that the standard of morality is raised just in proportion as Buddha-nature or real self extends and amplifies itself in different times and places.  Secondly, since good is Buddha-nature actualized to a large extent, and bad is also Buddha-nature actualized to a small extent, the existence of the former presupposes that of the latter, and the mess of duality can never be got rid of.  Thirdly, the fact that the bad become good under certain circumstances, and the good also become bad often unexpectedly, can hardly be explained by the dualistic theory, because if good nature be so arbitrarily turned into bad and bad nature into good, the distinction of good and bad nature has no meaning whatever.  According to the theory of Buddha-nature, the fact that the good become bad or the bad become good, does not imply in the least a change of nature, but the widening or the narrowing of its actualization.  So that no matter how morally degenerated one may be, he can uplift himself to a high ethical plane by the widening of his self, and at the same time no matter how morally exalted one may be, he can descend to the level of the brute by the narrowing of his self.  To be an angel or to be a devil rests with one’s degrees of enlightenment and free choice.  This is why such infinite varieties exist both among the good and the bad.  This is why the higher the peak of enlightenment the people climb, the more widely the vista of moral possibilities open before them.

14.  Buddha-Nature is the Common Source of Morals.

Furthermore, Buddha-nature or real self, being the seat of love and the nucleus of sincerity, forms the warp and woof of all moral actions.  He is an obedient son who serves his parents with sincerity and love.  He is a loyal subject who serves his master with sincerity and love.  A virtuous wife is she who loves her husband with her sincere heart.  A trustworthy friend is he who keeps company with others with sincerity and love.  A man of righteousness is he who leads a life of sincerity and love.