爱问：「至善只求诸心，恐于天下事理有不能尽。」
先生曰：「心即理也。天下又有心外之事、心外之理乎？」
爱曰：「如事父之孝、事君之忠、交友之信、治民之仁，其间有许多理在，恐亦不可不察。」
先生叹曰：「此说之蔽久矣，岂一语所能悟？今姑就所问者言之。且如事父，不成去父上求个孝的理？事君，不成去君上求个忠的理？交友、治民，不成去友上、民上求个信与仁的理？都只在此心，心即理也。此心无私欲之蔽，即是天理，不须外面添一分。以此纯乎天理之心：发之事父，便是孝；发之事君，便是忠；发之交友、治民，便是信与仁。只在此心『去人欲、存天理』上用功便是。」
爱曰：「闻先生如此说，爱已觉有省悟处。但旧说缠于胸中，尚有未脱然者。如事父一事，其间温凊、定省之类，有许多节目，不亦须讲求否？」
先生曰：「如何不讲求？只是有个头脑，只是就此心『去人欲、存天理』上讲求。就如：讲求『冬温』，也只是要尽此心之孝，恐怕有一毫人欲间杂；讲求『夏凊』，也只是要尽此心之孝，恐怕有一毫人欲间杂；只是讲求得此心。此心若无人欲，纯是天理，是个诚于孝亲的心：冬时自然思量父母的寒，便自要求个温的道理；夏时自然思量父母的热，便自要求个凊的道理。这都是那诚孝的心发出来的条件。却是须有这诚孝的心，然后有这条件发出来。譬之树木，这诚孝的心便是根，许多条件便是枝叶。须先有根，然后有枝叶；不是先寻了枝叶，然后去种根。《礼记》言：『孝子之有深爱者，必有和气。有和气者，必有愉色。有愉色者，必有婉容。』须是有个『深爱』做根，便自然如此。」
徐爱问：「至善只从心上寻求，恐怕对天下的事理不能穷尽。」
先生说：「心就是理。天下难道还有心外之事、心外之理吗？」
徐爱说：「比如侍奉父亲的孝、侍奉君主的忠、结交朋友的信、治理百姓的仁，这中间有许多道理在，恐怕也不能不加考察。」
先生叹道：「这种说法的蒙蔽已经很久了，岂是一句话能让人醒悟的？现在姑且就你所问的来说。比如侍奉父亲，难道去父亲身上求个孝的理？侍奉君主，难道去君主身上求个忠的理？交友、治民，难道去朋友、百姓身上求个信与仁的理？都只在这心上，心就是理。这颗心没有被私欲遮蔽，就是天理，不需要从外面添加一分。以这颗纯乎天理的心：发出来侍奉父亲，便是孝；发出来侍奉君主，便是忠；发出来交友、治民，便是信与仁。只需在这心上『去人欲、存天理』用功便是。」
徐爱说：「听先生这样讲，我已经觉得有省悟之处。但旧说缠在胸中，还有未能完全脱开的。比如侍奉父亲一件事，其中冬温夏凊、昏定晨省之类，有许多细节节目，不也需要讲求吗？」
先生说：「怎么不讲求？只是要有个头脑，只是就在这心『去人欲、存天理』上讲求。就像讲求『冬温』，也只是要尽此心之孝，唯恐有一毫人欲夹杂；讲求『夏凊』，也只是要尽此心之孝，唯恐有一毫人欲夹杂；讲求的只是要得此心。此心若无人欲，纯是天理，是一颗诚于孝亲的心：冬天自然会想着父母的寒冷，便自然要去求个保暖的道理；夏天自然会想着父母的暑热，便自然要去求个纳凉的道理。这都是那诚孝的心发出来的具体条目。必须是先有这颗诚孝的心，然后才有这些条目发出来。譬如树木，这诚孝的心便是根，许多条目便是枝叶。必须先有根，然后有枝叶；不是先找来枝叶，然后去种根。《礼记》说：『孝子中有深爱的，必有和气；有和气的，必有愉色；有愉色的，必有婉容。』必须有个『深爱』作根，便自然如此。」
Xu Ai asked: "If the highest good is sought only in the mind, I fear the principles of all affairs under heaven cannot be exhausted."
The Master said: "The mind itself is principle. Is there any affair or principle outside the mind under heaven?"
Xu Ai said: "Take filial piety in serving a father, loyalty in serving a ruler, good faith with friends, humaneness in governing the people — there are many principles involved; surely they must be examined."
The Master sighed: "This doctrine has blinded people for long; can one sentence awaken you? Let me speak to your question. In serving a father, does one go to the father to seek the principle of filial piety? In serving a ruler, does one seek the principle of loyalty from the ruler? With friends and the people, does one seek good faith and humaneness from them? It all lies in this very mind: the mind is principle. When this mind is not obscured by selfish desire, it is heavenly principle itself; nothing need be added from outside. With this mind pure in heavenly principle: expressed in serving a father, it is filial piety; in serving a ruler, loyalty; with friends and in governing the people, good faith and humaneness. One need only work at 'removing human desire and preserving heavenly principle' in this mind."
Xu Ai said: "Hearing this I sense some awakening, but old views still cling. Take serving one father: there are many details — warming in winter, cooling in summer, settling at dusk and inquiring at dawn. Must these not be studied?"
The Master said: "Of course they must — but with a guiding head: study them precisely on 'removing human desire and preserving heavenly principle' in this mind. Studying 'warming in winter' is only to exhaust this mind's filial piety, fearing any taint of selfish desire; the same for cooling in summer. What is sought is this very mind. If the mind is free of selfish desire, pure heavenly principle — a mind sincerely filial — then in winter it naturally thinks of the parents' cold and seeks the way to warm them; in summer, of their heat and seeks the way to cool them. All these are conditions issuing from that sincerely filial mind. There must first be this sincere filial mind, and only then do these conditions arise. It is like a tree: the sincere mind is the root, the many conditions are branches and leaves. First the root, then the branches — not gathering branches first and then planting a root. The Record of Rites says: 'The filial child of deep love must have gentle air; gentle air, a pleasant countenance; a pleasant countenance, soft and compliant bearing.' There must be deep love as the root, and all this follows naturally."