来书云：「所喻知行并进，不宜分别前后。即《中庸》『尊德性而道问学』之功，交养互发、内外本末一以贯之之道。然工夫次第，不能无先后之差。如知食乃食，知汤乃饮，知衣乃服，知路乃行，未有不见是物，先有是事。此亦毫厘倏忽之间，非谓截然有等，今日知之而明日乃行也。」
既云「交养互发、内外本末一以贯之」，则知行并进之说无复可疑矣。又云：「工夫次第，不能不[1]无先后之差。」无乃自相矛盾已乎？「知食乃食」等说，此尤明白易见，但吾子为近闻[2]障蔽，自不察耳。夫人必有欲食之心，然后知食；欲食之心即是意、即是行之始矣。食味之美恶，必待入口而后知。岂有不待入口而已先知食味之美恶者邪？必有欲行之心，然后知路；欲行之心即是意、即是行之始矣；路岐之险夷，必待身亲履历而后知。岂有不待身亲履历，而已先知路岐之险夷者耶？「知汤乃饮」，「知衣乃服」，以此例之，皆无可疑。若如吾子之喻，是乃所谓不见是物而先有是事者矣。吾子又谓：「此亦毫厘倏忽之间，非谓截然有等今日知之，而明日乃行也。」是亦察之尚有未精。然就如吾子之说，则知行之为合一并进[3]，亦自断无可疑矣。
来信说：「您说知行并进，不宜分出先后。也就是《中庸》『尊德性而道问学』的功夫，交相涵养、互相引发、内外本末一以贯之之道。然而功夫的次第，不能没有先后的差别。如知道食物才吃、知道汤才饮、知道衣服才穿、知道路才走，没有不见到那东西、先有那事情的。这也只在毫厘倏忽之间，并不是截然分等、今天知道明天才去做。」
既然说「交养互发、内外本末一以贯之」，那么知行并进之说就无可疑了。又说「功夫次第，不能没有先后的差别」，岂不是自相矛盾吗？「知食乃食」等说法尤其明白易见，只是您被近来的闻见障蔽，自己不察觉罢了。人必定先有想吃的心，然后才知道食物；想吃的心就是意，就是行的开始了。食物味道的好坏，必须等入口之后才知道，哪有不待入口就已先知道味道好坏的？必定先有想走的心，然后才知道路；想走的心就是意，就是行的开始了；道路的险夷，必须亲自经历才知道，哪有不亲身经历就已先知道路途险夷的？「知汤乃饮」「知衣乃服」，照此类推，都无可疑。若照您的比喻，那才是所谓不见其物而先有其事了。您又说「这也只在毫厘倏忽之间，并不是截然分等、今天知道明天才行」，这也是省察得还不够精。然而照您的说法，知行的合一并进，也自然断然无可疑了。
Your letter says: 'You hold knowledge and action advance together without before or after — as the Mean says, honoring the moral nature while pursuing inquiry, mutually nourishing, inner and outer, root and branch one thread through. Yet the order of work cannot lack sequence: knowing food, one eats; knowing the soup, drinks; knowing clothes, dresses; knowing the road, walks — never the deed before the thing is seen. This is a hairspread-in-an-instant, not a hard division of knowing today and acting tomorrow.'
Having granted mutual nourishment and one thread through inner and outer, root and branch, the advance-together of knowledge and action needs no further defense. To add that the order of work cannot lack before-and-after — is that not contradicting yourself? The examples of eating and the rest are the plainest of all; only your recent habits veil them from you. One must first have the desire to eat, and then knows food; the desire to eat is intention, is already the beginning of action. Whether the food is good or ill is known only after it enters the mouth — who knows it before? One must first will to travel, then knows the road; the will to travel is intention, the beginning of action; the road's dangers are known only by treading it oneself. Soup and clothing follow the same rule. On your own figure, it would be the deed before the thing seen. Your further remark — that it is only a hairspread in an instant, not know today and act tomorrow — still wants fineness. Yet even on your terms, the union and advance of knowledge and action admit no doubt.
- 据来书，原文「不」字显系误印。施本、张本无「不」字。
- 「近闻」指朱熹为主的知先行后说。
- 王守仁此处「合一并进」即合一之义。「并进」二字系未经详细斟酌所用语。