问「通乎画夜之道而知」。
先生曰：「良知原是知画知夜的。」
又问：「人睡熟时，良知亦不知了。」
曰：「不知何以一叫便应？」
曰：「良知常知，如何有睡熟时？」
曰：「向晦宴息，此亦造化常理。夜来天地混沌，形色俱泯，人亦耳目无所睹闻，众窍俱翕，此即良知收敛凝一时。天地既开，庶物露生，人亦耳目无所赌闻，众窍俱辟，此即良知妙用发生时。可见人心与天地一体，故上下与天地同流。今人不会宴息，夜来不是昏睡，则是妄思[1]魇寐。」
曰：「睡时功夫如何用？」
先生曰：「知昼即知夜矣。日间良知是顺应无滞的，夜间良知即是收敛凝一的，有梦即先兆。」
问「通乎昼夜之道而知」。
先生说：「良知原本是知昼知夜的。」
又问：「人睡熟时，良知也就不知了。」
答：「不知怎么一叫便应？」
问：「良知常知，怎么会有睡熟的时候？」
答：「向晚休息，这也是造化的常理。夜里天地混沌，形色俱泯，人也耳目无所见闻，众窍都闭合，这就是良知收敛凝一的时候。天地既开，万物露生，人也耳目有所见闻，众窍都开张，这就是良知妙用发生的时候。可见人心与天地一体，所以上下与天地同流。今人不会休息，夜里不是昏睡，就是妄思魇寐。」
问：「睡时功夫怎么用？」
先生说：「知昼就知夜了。白天良知是顺应无滞的，夜间良知就是收敛凝一的，有梦便是先兆。」
Asked about comprehending the way of day and night.
The Master said: 'Innate knowledge knew the day and knows the night.'
Asked again: 'In deep sleep it seems not to know.'
'Not knowing — how does one call and it answers?'
'If innate knowledge ever knows, whence deep sleep?'
'Rest at dusk is the constant law of creation. At night heaven and earth blur, form and color sink; man's ears and eyes take in nothing, every aperture closes — that is innate knowledge gathered and made one. Heaven and earth open, the things spring forth into view, the apertures open — that is its wondrous working flowing forth. Thus the human heart is one body with heaven and earth, streaming with them above and below. Today's men know not how to rest: their nights are either dead sleep or wild dreams.'
'How is the work applied in sleep?'
'Know the day and you know the night. By day innate knowledge meets all without friction; by night it gathers and unites — dreams are its forerunners.'
- 「妄思」，俞本作「妄想」。