禪林寶訓 2.31

2.31

靈源謂圓悟曰。衲子雖有見道之資。若不深蓄厚養。發用必峻暴。非特無補教門。將恐有招禍辱。圓悟禪師曰。學道存乎信。立信在乎誠。存誠於中。然後俾眾無惑。存信於己。可以教人無欺。惟信與誠有補無失。是知誠不一則心莫能保。信不一則言莫能行。古人云。衣食可去誠信不可失。惟善知識當教人以誠信。且心既不誠事既不信。稱善知識可乎。易曰。惟天下至誠遂能盡其性。能盡其性則能盡人之性。而自既不能盡於己。欲望盡於人。眾必紿而不從。自既不誠於前。而曰誠於後。眾必疑而不信。所謂割髮宜及膚。剪爪宜侵體。良以誠不至則物不感。損不至則益不臻。蓋誠與信不可斯須去已也明矣（與虞察院書）。

Lingyuan said to Yuanwu, "Although a patch-robed monk may have the endowment to see the Way, if they do not store it deeply and nurture it richly, their deployment of it will surely be harsh and violent. Not only will it fail to benefit the teachings, it will also be feared to invite disaster and disgrace." Chan Master Yuanwu said, "Studying the Way lies in trustworthiness; establishing trustworthiness lies in sincerity. Preserve sincerity within, and thereafter you will cause the multitude to have no doubts. Preserve trustworthiness in yourself, and you can teach others to be without deception. Only with trustworthiness and sincerity will there be benefit and no loss. From this we know that if sincerity is not unified, the mind cannot be preserved; if trustworthiness is not unified, one's words cannot be put into practice. The ancients said, 'Food and clothing may be abandoned, but sincerity and trustworthiness cannot be lost.' Kalyāṇamitras especially should instruct people with sincerity and trustworthiness. Moreover, if the mind is not sincere and deeds are not trustworthy, can one be called a kalyāṇamitra? The *Changes* says: 'Only the utmost sincerity under Heaven can fully develop its nature; being able to fully develop its nature, it can fully develop the nature of others.' If one cannot fully develop it in oneself yet desires to fully develop it in others, the multitude will surely deceive and not follow. If one was not sincere before, yet claims to be sincere afterward, the multitude will surely doubt and not believe. It is said, 'Cutting the hair should reach the scalp; trimming the nails should cut into the flesh.' Truly, if sincerity is not consummate, things will not respond; if diminishing oneself is not consummate, benefit will not arrive. Indeed, it is clear that sincerity and trustworthiness cannot be parted from for an instant." (Letter to Censor Yu)