The terms du (獨) and shendu (慎獨) frequently appear in transmitted texts, notably, among others, the Xunzi and Liji. Drawing reference from the poetry of “Shijiu” (鳲鳩) (Ode 152) and “Yanyan” (燕燕) (Ode 28) in the Book of Odes (詩經), the recovered texts of “Wuxing Commentary” (五行 說) and “Confucian Poetics” (孔子詩論) have provided new material for re-shaping our current understanding of the concepts of du and shendu. This study will briefly survey the semantic ranges of these terms within the exegetical tradition and explore their meaning with regard to the poetry from which they are contextualized. In the final analysis du can be understood as the ontic quality of the heart-mind within the broad sense of cheng (誠 sincerity), or devout love, whereas shendu can be regarded as a process of moral cultivation. To some extent the re-interpretation of these terms finds commonality with, rather than subverts, the semantic ranges established by traditional glosses. The recovered texts have enhanced our understanding of these terms, in particular the concepts of heart-mind and emotion in early China.