The transition from Greek philosophy to Patristic philosophy is an issue rarely addressed in Chinese scholarship. This paper is taking up the issue and examine its significance in the history of western thought. As an initial suggestion, firstly, I am analyzing into the conceptual connection between the impasse of Greek skepticism, into which Greek philosophers in their pursuits for truth get stuck, and the response to it provided by Christian thinkers in terms of the concept of grace. And then, I am endeavoring to demonstrate the concept of grace in the gospel of John, as well as perceived by early church fathers, and further its relevance to the issue of truth. One significant feature in their efforts is that they had shown the epistemological power of grace, which have then become the driving force in the development of western thought.