门人问曰：「知行如何得合一？且如《中庸》言『博学之』，又说个『笃行之』；分明知行是两件。」
先生曰：「博学只是事事学存此天理，笃行只是学之不已之意。」
又问：「《易》『学以聚之』，又言『仁以行之』。此是如何？」
先生曰：「也是如此。事事去学存此天理，则此心更无放失时，故曰『学以聚之』。然常常学存此天理，更无私欲间断，此即是此心不息处，故曰『仁以行之』。」
又问：「孔子言『知及之，仁不能守之』，知行却是两个了。」
先生曰：「说『及之』，已是行了。但不能常常行，已为私欲间断，便是『仁不能守』。」
又问：「心即理之说，程子云『在物为理』。如何谓心即理？」
先生曰：「在物为理，『在』字上当添一『心』字。此心在物则为理。如此心在事父则为孝，在事君则为忠之类。」
先生因谓之曰：「诸君要识得我立言宗旨。我如今说个心即理是如何，只为世人分心与理为二，故便有许多病痛。如五伯的攘夷狄、尊周室，都是一个私心，便不当理。人却说他做得当理，只心有未纯，往往悦慕其所为，要来外面做得好看，却与心全不相干。分心与理为二，其流至于伯道之伪而不自知。故我说个心即理，要使知心、理是一个。便来心上做工夫，不去袭义于外，便是王道之真。此我立言宗旨。」
又问：「圣贤言语许多，如何却要打做一个？」
曰：「我不是要打做一个，如曰：『夫道，一而已矣。』又曰：『其为物不二，则其生物不测。』天地圣人皆是一个，如何二得？」
门人问：「知行怎么能合一？比如《中庸》说『博学之』，又说『笃行之』，分明知行是两件。」
先生说：「博学只是事事学习存此天理，笃行只是学个不止息的意思。」
又问：「《易经》说『学以聚之』，又说『仁以行之』，这是怎样？」
答：「也是如此。事事去学存此天理，此心便再无放失的时候，所以说『学以聚之』。常常学存此天理，再没有私欲间断，这便是此心不息处，所以说『仁以行之』。」
又问：「孔子说『知及之，仁不能守之』，知行又成两个了。」
答：「说『及之』，已经是行了。只是不能常常去行，被私欲间断，便是『仁不能守』。」
又问：「『心即理』之说，程子却说『在物为理』，怎么说心即理？」
答：「『在物为理』，『在』字上应添一个『心』字。此心在物则为理：如此心在事父则为孝，在事君则为忠之类。」
先生于是对大家说：「诸位要认得我立言的宗旨。我如今说个心即理是为什么？只因世人把心与理分作二，所以有许多病痛。比如五霸的驱逐夷狄、尊崇周室，都是一个私心，便不合于理。人却说他们做得合理，只是心还不纯，往往欣慕他们所为，要在表面上做得好看，却与心全不相干。把心与理分作二，流弊所至，至于行霸道之虚伪而自己不知道。所以我说个心即理，要使人知道心与理是一个，便在心上做功夫，不去外面袭取义，这才是王道之真。这是我的立言宗旨。」
又问：「圣贤的言语那么多，为什么却要打成 一个？」
答：「我不是硬要打成 一个。比如孟子说『夫道，一而已矣』，《中庸》说『其为物不二，则其生物不测』。天地圣人都是一个，怎么分成两个？」
A disciple asked: 'How can knowledge and action be one? The Mean says learn broadly, then adds practice it in earnest — plainly two things.'
The Master said: 'Broad learning is learning, affair by affair, to preserve this principle; earnest practice is learning without stopping.'
Asked: 'The Changes says by learning gather it, by humaneness carry it out — how?'
'So too. Learning in each affair to preserve principle, the heart never strays — hence gathering. Ever learning to preserve it, no private desire breaking in — that is the heart's unresting, hence carrying it out.'
'Confucius: knowledge reaches it, humaneness cannot hold it — two again.'
'Reaches it is already acting. Only failing to act constantly, broken by private desire, is humaneness not holding.'
'And your mind-is-principle against Chengzi's in things is principle?'
'In things is principle wants a mind added before in: this mind in the thing is principle — in serving a father, filial piety; a ruler, loyalty.'
And to them all: 'Know my purport. Why do I say mind is principle? Only because the world splits mind and principle in two, breeding all these sicknesses. The five hegemons' expelling the barbarians and honoring the house of Zhou were one private heart — off principle. Yet men call their deeds right, only their hearts impure, admiring the doing, making a fair show outside with the heart nothing to do with it. Splitting mind and principle, the stream runs down to the hypocrisy of the hegemon's way unawares. Hence I say mind is principle, to have men know the two are one and work upon the mind, not snatching rightness from outside — that is the true royal way. That is my purport.'
Asked why the sages' many words must be beaten into one: 'Not beaten — the Way is one, that is all; its being undoubled is why its engendering is past fathoming. Heaven and earth and the sages are each one — how two?'