「敬」是朱子工夫論的核心概念，它在心性論中的定位不僅關係到修身工夫何以可能，甚至決定了朱子理論形態的歸屬。儘管朱子並未給出直接的答案，但檢閱其相關論述，可以推論「敬」應是「恭敬之心」之一面，亦即以「禮」之德為「頭腦」的「情」。此種理解可能面臨「敬」的「未發已發」問題。這一問題可通過辨析「未發已發」的兩種含義予以解決，同時還可引出兩個考察「敬」之定位的視角。由此可知，「敬」不僅是一種修身工夫，亦是一種源自性理的道德之情，因而絕非牟宗三所說的「空頭的涵養」。

Ching is the core concept of Chu Tzu’s theory of self-cultivation. Its positioning in the theory of mind not only relates to the possibility of self-cultivation, but also determines the attribution of Chu Tzu’s theoretical form. Although he does not give a direct answer, it can be inferred from reviewing his relevant discussion that Ching should be one side of respectful mind, that is, the ch’ing with the virtue of li as mastermind. Such an understanding may face the problem that Ching is i-fa or wei-fa, but it can be solved by distinguishing the two meanings of i-fa and wei-fa., which will lead to two perspectives to examine the position of Ching. It can be seen that Ching is not only a kind of self-cultivation effort, but also a kind of moral feeling derived from moral nature. Therefore, it is not the rootless self-cultivation that Mou Tsung-san said.