This paper, in six sections, re-evaluates Yan Fu’s xin, da, ya, or faithfulness, intelligibility, elegance of style, and interprets his notion of cheng (commitment, sincerity, truth) based on Michel Foucault’s theory of discourse. The first section discusses the origins of xin, da, ya. Discourse in Foucault’s definition is adopted as the methodology for this paper where “xin, da, ya” is considered one of the various discourses in the history of translation in China. The second section applies Foucault’s concept of the “will to truth” to xin and concludes that the will to translational faithfulness does not guarantee the translation to be faithful to the original. The third section focuses on language and how the disparities between the signifier and the signified as well as those between different languages are ironed out as a result of our obstinate will to knowledge and power, which helps to shape our idea of da. The fourth section approaches ya from the concept of Foucault’s épistémè and finds that the mainstream style of a period is largely decided by the structure of thought unique to it. In the fifth section, the author argues that the notion of cheng only is what deeply influences Yan Fu as a translator. In addition to reconsidering the value of xin, da, ya in its modern context, the final section concludes that Yan Fu’s cheng, or his commitment to translation, as compared with xin, da, ya, is more deserving of our imitation.