The Collected Conversations of Master Zhu 朱子語類 contain 140 chapters of conversations as recorded by his students at his academies (think of them as student-teacher Q&A), which circulated as their own form of Song Dynasty social media, before being first compiled in the year 1270. As I encounter key sayings they will be translated here.

1:22 A pupil asked about the word “Tian” 天 in the classics. Zhu Xi said: “This requires one's own capacity to discern, parse, and understand clearly. There are those who say it refers to the vast blue sky (cang cang 蒼蒼), those who say it means the master or sovereign (zhu zai 主宰), and there are times when it simply means principle (li 理).”

又僩問經傳中「天」字。曰：「要人自看得分曉，也有說蒼蒼者，也有說主宰者，也有單訓理時。」

5:2 Principle (li 理) is the substance of heaven; fate (ming 命) is the function of principle. Nature (xing 性) is what humans receive; disposition (qing 情) is the function of one’s nature.

理者，天之體；命者，理之用。性是人之所受，情是性之用。

7:1

The ancients, during their early years, entered elementary learning (xiaoxue 小學), which simply taught with matters such as rites, music, archery, chariot-driving, calligraphy, arithmetic, as well as matters of loyalty, trustworthiness, family affection and respect for elders.

From the age of sixteen or seventeen, those who entered greater learning (daxue大學) were then taught with principles, such as the extension of knowledge, the investigation of things, as well as the reasons for why we act with loyalty, trustworthiness, and respect for the family.

古者初年入小學，只是教之以事，如禮樂射御書數及孝弟忠信之事。自十六七入大學，然後教之以理，如致知、格物及所以為忠信孝弟者。

° ° °

7:4 The ancient people's elementary education nourished the development of young children's sincerity (cheng 誠) and seriousness (jing 敬); the beginnings of goodness became clearly apparent. However, for greater learning equivalent matters, it's not suitable to push young children into them; hence, they later entered greater learning to teach that.

古人小學養得小兒子誠敬善端發見了。然而大學等事，小兒子不會推將去，所以又入大學教之。

14:綱領:3 One might ask that people first read the Great Learning in order to establish the [Confucian Way’s] framework. Next the Discourses to ground its fundamentals. Then the Mengzi to observe its development. And finally the Doctrine of the Mean to strive for the ancients’ subtly mysterious insights.

The Great Learning, in a single piece of writing, provides graded steps and an order to be followed; always to be regarded as a whole, it is easy to understand and should be looked at first. The Discourses, even though real and substantial, appear broken and scattered in its dialogue; at first look it is too difficult. The Mengzi has passages that arouse feelings and inspire development in men’s minds. The Doctrine of the Mean is also difficult to study; look at the other three books, only afterward is it appropriate to read it.

某要人先讀大學，以定其規模；次讀論語，以立其根本；次讀孟子，以觀其發越；次讀中庸，以求古人之微妙處。大學一篇有等級次第，總作一處，易曉，宜先看。論語卻實，但言語散見，初看亦難。孟子有感激興發人心處。中庸亦難讀，看三書後，方宜讀之。

19:61 In the Discourses and Mengzi, for over forty years, I have been connecting principles, weighing each character, and so on, without allowing even a slight inclination to one side. Scholars, with the points of my commentary, should examine them carefully.

中庸解每番看過，不甚有疑。大學則一面看，一面疑，未甚愜意，所以改削不已。

Someone asked about the phase “without sincerity, there is nothing.”

Answer: Sincerity (cheng 誠) is reality. Take family feelings (xiao 孝), for example. If one is not real in these, then it is merely empty talk. Without this filiality, then already it is the case that without sincerity, there is nothing. [64: Zhong Yong 25: 21]

或問「不誠無物」。曰：「誠，實也。且如為孝，若不實是孝，便是空說，無這孝了，便是『不誠無物』。」

Source: the “Collected Conversations of Master Zhu,” Qing Dynasty imperial edition. From Zhejiang University Library, scanned by China-America Digital Academic Library (CADAL). Digitized Chinese text, with corresponding index numbers, is available at the Chinese Text Project (CTEXT).