来书云：「有引程子『人生而静以上不容说；才说性，便已不是性』。何故不容说？何故不是性？晦庵答云：『不容说者，未有性之可言；不是性者，已不能无气质之杂矣。』二先生之言皆未能晓，每看书至此，辄为一惑，请问。」
「生之谓性」，「生」字即是「气」字，犹言「气即是性」也。气即是性，「人生而静以上不容说」，才说「气即是性」，即已落在一边，不是性之本原矣。孟子「性善」，是从本原上说。然性善之端，须在气上始见得；若无气，亦无可见矣。恻隐、羞恶、辞让、是非即是气。程子谓：「论性不论气，不备；论气不论性，不明。」亦是为学者各认一边，只得如此说。若见得自性明白时，气即是性，性即是气，原无性、气之可分也。
来信说：「有人引程子的话『人生而静以上不容说，才说性便已不是性』。为什么不容说？为什么已不是性？朱子答道：『不容说的，是还没有性可言；不是性的，是已不能没有气质的夹杂了。』两位先生的话我都不明白，每次看书到这里就疑惑，请指教。」
「生之谓性」的「生」字就是「气」字，等于说「气即是性」。气即是性，「人生而静以上不容说」，才说「气即是性」，便已落在一边，不是性的本原了。孟子讲「性善」，是从本原上说的。然而性善的发端，必须在气上才见得；没有气，也就无可见了。恻隐、羞恶、辞让、是非就是气。程子说：「论性不论气，不备；论气不论性，不明。」也是因为学者各认一边，只得这样说。若见得自性明白时，气即是性，性即是气，原本没有性、气可分。
Your letter says: 'Someone cites Chengzi: above man's birth-into-stillness nothing can be said; the moment you speak of nature it is already not nature. Why can nothing be said? Why is it no longer nature? Zhu Xi answered: nothing can be said because no nature is yet assertable; not nature because the admixture of stuff is already there. Both masters' words escape me; every time I read to this point I stumble. Please instruct.'
In life is what is called nature, life is but breath: breath itself is nature. Breath being nature, above birth-into-stillness nothing can be said: the moment one says breath-is-nature one has fallen to one side, no longer nature's source. Mencius's nature-good speaks from the source. Yet nature's goodness of sprouting shows only upon breath; without breath, nothing to see. Compassion, shame, deference, right-and-wrong are breath. Chengzi's treating nature without breath is incomplete; breath without nature, unclear — said only because learners each clung to one side. When one's own nature is seen in clarity, breath is nature, nature breath — originally no dividing them.