澄问：「喜怒哀乐之中、和，其全体常人固不能有。如一件小事当喜怒者，平时无有喜怒之心，至其临时，亦能中节，亦可谓之中、和乎？」
先生曰：「在一时一事，固亦可谓之中、和，然未可谓之大本、达道。人性皆善，中、和是人人原有的，岂可谓无？但常人之心既有所昏蔽，则其本体虽亦时时发见，终是暂明暂灭，非其全体大用矣。无所不中，然后谓之『大本』；无所不和，然后谓之『达道』。惟天下之至诚，然后能立天下之『大本』。」
曰：「澄于『中』字之义尚未明。」
曰：「此须自心体认出来，非言语所能喻。『中』只是天理。」
曰：「何者为天理？」
曰：「去得人欲，便识天理。」
曰：「天理何以谓之中？」
曰：「无所偏倚。」
曰：「无所偏倚是何等气象？」
曰：「如明镜然，全体莹彻，略无纤尘染著。」
曰：「偏倚是有所染著。如著在好色、好利、好名等项上，方见得偏倚；若未发时，美色、名、利皆未相著，何以便知其有所偏倚？」
曰：「虽未相著，然平日好色、好利、好名之心原未尝无；既未尝无，即谓之有；既谓之有，则亦不可谓无偏倚。譬之病疟之人，虽有时不发，而病根原不曾除，则亦不得谓之无病之人矣。须是平日好色、好利、好名等项一应[1]私心，扫除荡涤，无复纤毫留滞，而此心全体廓然，纯是天理，方可谓之『喜怒哀乐未发之中』，方是『天下之大本』。」
陆澄问：「喜怒哀乐的中与和，它的全体常人固然不能具有。比如一件应当喜怒的小事，平时没有喜怒之心，到临事时也能合乎节度，这也可以叫中与和吗？」
先生说：「就一时一事而言，固然也可以叫中与和，但还不能叫大本与达道。人性皆善，中与和是人人原本就有的，怎么能说没有？只是常人的心既有所昏蔽，它的本体虽然也时时显现，终究是忽明忽灭，不是全体大用了。无所不中，然后才叫『大本』；无所不和，然后才叫『达道』。只有天下至诚的人，才能确立天下的『大本』。」
问：「我对『中』字的含义还未明白。」
答：「这必须从自己心上体认出来，不是言语所能说明的。『中』只是天理。」
问：「什么是天理？」
答：「去掉了人欲，便识得天理。」
问：「天理为什么叫作中？」
答：「因为无所偏倚。」
问：「无所偏倚是什么气象？」
答：「如同明镜，全体晶莹透彻，没有一点纤尘沾染。」
问：「偏倚是有所沾染。比如沾在好色、好利、好名等项目上，才看得出偏倚；若未发时，美色名利都还没有附着，怎么就知道它有所偏倚呢？」
答：「虽然还没有附着，但平日好色、好利、好名之心原本不曾没有；既然不曾没有，就叫作有；既然叫作有，也就不能说无偏倚。比如患疟疾的人，虽然有时不发作，但病根原不曾除去，也就不能说他是无病之人了。必须是平日好色、好利、好名等一切私心扫除荡涤，没有丝毫滞留，这颗心全体廓然，纯是天理，才可以叫『喜怒哀乐未发之中』，才是『天下之大本』。」
Lu Cheng asked: 'The fullness of equilibrium and harmony in joy, anger, sorrow, pleasure is surely beyond ordinary people. Yet take some small matter that should stir feeling: if one has felt nothing beforehand and the response stays in measure, is that not equilibrium and harmony too?'
The Master said: 'For the moment and the single affair it may be so called, but not yet the great root and the reached Way. Human nature is all good; equilibrium and harmony belong to everyone originally — how could they be absent? But the ordinary mind is dimmed and veiled; its substance shows forth from time to time, flaring and failing, not its whole substance and great functioning. Equilibrium everywhere, then it is the great root; harmony everywhere, then it is the reached Way. Only the utterly sincere under Heaven can establish the great root.'
'I do not yet grasp the meaning of equilibrium.'
'It must be recognized out of your own mind; words cannot convey it. Equilibrium is heavenly principle.'
'What is heavenly principle?'
'Remove human desire, and you know heavenly principle.'
'Why is heavenly principle called equilibrium?'
'Because it leans nowhere.'
'What is that like?'
'Like a bright mirror, wholly luminous, not a speck of dust clinging.'
'Leaning means clinging — to beauty, gain, fame. But before arousal, none of these has yet attached itself; how do we know the mind leans?'
'Though not yet attached, the daily desires for beauty, gain and fame were never absent; never absent, they must be called present; and if present, the mind cannot be said not to lean. Like a man with malaria: though the fit is quiet, the root was never removed — he cannot be called well. Only when every private desire has been swept away without a thread remaining, the mind's whole substance vast and pure in heavenly principle, can it be called the equilibrium before joy, anger, sorrow and pleasure — the great root of all under Heaven.'
- 一应：一切。