北宋時期，有許多重要的士大夫關注「君子」和「小人」這兩個傳統儒學概念在政治和思想上的含義，一方面是因為政治黨派鬥爭的激烈化，另一方面也受到新的心性學說的影響。歐陽修、范仲淹、王安石、胡瑗及司馬光等重要思想家，均依據儒家經典，試著重新詮釋這兩個概念的意涵。在此思想背景下，本文集中探討司馬光對於君子和小人的看法，試圖釐清兩者在他的思想中的重要性為何。針對這個問題，司馬光所編輯的《太玄集注》是關鍵性的資料。司馬光推崇揚雄的思想，認為他在《太玄經》內區別君子與小人的不同，並列出具體的例子教導士人如何避免成為小人，而是成為君子。對司馬光而言，《太玄經》提供一個適用各種時空處境的行動範式，使讀者思考君子與小人的言行在各式情況下如何導致不同結果。總之，在《太玄集注》中，司馬光想突出《太玄經》的某些價值：幫助士大夫治心、修德、處事應物，同時助人成為君子。

During the Northern Song dynasty, the problem of how to define the traditional Confucian concepts of the cultivated man (junzi 君子) and the small man (xiaoren 小人) became an important topic of debate. This debate was influenced by the factional infighting that plagued Northern Song politics, as well as the development of new ideas regarding the human mind, the nature and self-cultivation. Drawing on passages found in classical texts, particularly the Yijing, many Northern Song thinkers, such as Ouyang Xiu, Fan Zhongyan, Wang Anshi, and Hu Yuan sought to delineate the political and philosophical implications inherent in these terms. The present article investigates how the influential Northern Song intellectual and statesman, Sima Guang, interpreted the concepts of junzi and xiaoren in his various writings. It is argued here that his Collected Commentaries on the Taixuan jing is a key text for understanding his views on the junzi and xiaoren and furthermore that these terms played a very important role in Sima’s philosophical thought.