来书云：「养生以清心寡欲为要。夫清心寡欲，作圣之功毕矣。然欲寡则心自清。清心非舍弃人事而独居求静之谓也。盖欲使此心纯乎天理，而无一毫人欲之私耳。今欲为此之功，而随人欲生而克之，则病根常在，未危灭于东而生于西。若欲刊剥洗荡于众欲未萌之先，则又无所用其力，徒使此心之不清。且欲未萌而搜剔以求去之，是犹引犬上堂而逐之也，愈不可矣。」
必欲此心纯乎天理，而无一毫人欲之私，此作圣之功也。必欲此心纯乎天理，而无一毫人欲之私，非防于未萌之先而克于方萌之际不能也。防于未萌之先而克于方萌之际，此正《中庸》「戒慎恐惧」、《大学》「致知格物」之功，舍此之外，无别功矣。
夫谓灭于东而生于西，引犬上堂而逐之者，是自私自利，将迎意必之为累，而非克治洗荡之为患也。今曰「养生以清心寡欲为要」，只「养生」二字，便是自私自利、将迎意必之根。有此病根潜伏于中，宜其有「灭于东而生于西」、「引犬上堂而逐之」之患也。
来信说：「养生以清心寡欲为要。清心寡欲，作圣的功夫也就完备了。然而欲寡则心自清。清心并不是舍弃人事而独居求静的意思，是要使此心纯乎天理、没有一毫人欲之私罢了。如今要做这个功夫，随着人欲生起便去克治，那么病根常在，扑灭于东而生于西。若想在众欲未萌之先就把它扫荡干净，又无处用力，徒使此心不清。而且欲念未萌却去搜剔以求去掉它，这就像把狗引上堂再来赶它，越发不行了。」
必欲此心纯乎天理、无一毫人欲之私，这正是作圣的功夫。必欲此心纯乎天理，非在未萌之先防范、在方萌之际克治不可。防于未萌之先而克于方萌之际，这正是《中庸》「戒慎恐惧」、《大学》「致知格物」的功夫，除此以外没有别的功夫。
至于说「灭于东而生于西」「引犬上堂而逐之」，那是自私自利、将迎意必造成的拖累，并不是克治洗荡的祸患。如今说「养生以清心寡欲为要」，只「养生」两个字，便是自私自利、将迎意必的根。有这个病根潜伏心中，难怪有「灭于东而生于西」「引犬上堂而逐之」的毛病了。
Your letter says: 'Nourishing life takes a clear mind and scant desire as the essential. With clear mind and scant desire, the work of sage-making is complete. Yet desire scant, the mind clears of itself. Clearing the mind does not mean quitting human affairs to dwell alone seeking quiet; it means making this mind pure in heavenly principle without a hair of private desire. Now to do this work, mastering desire as it springs, leaves the root of sickness ever there — quenched in the east, sprouting in the west. To sweep the desires before they sprout leaves nowhere to apply strength and only muddies the mind. And to ferret out desires not yet sprouted in order to remove them is leading the dog into the hall and then chasing it out — worse still.'
To will this mind pure in heavenly principle without a hair of private desire is precisely the work of sage-making. And that cannot be done except by guarding before the sprouting and mastering at the moment of sprouting. Guarding before and mastering at the moment is exactly the Mean's vigilance and fear and the Learning's extension and investigation — beyond this there is no other work.
As for springing in the west when quenched in the east, leading the dog in and chasing it out — those are the encumbrances of self-serving, of forestalling and presuming, not faults of mastering and sweeping. To say nourishing life takes a clear mind and scant desire: the two words nourishing life are themselves the root of self-serving, forestalling and presuming. With that root lurking within, no wonder the quench-in-the-east, dog-in-the-hall troubles appear.