虔敬是柏拉圖神學思想的核心理念。柏拉圖這篇以虔敬為主題的對話《遊敘弗倫》，更是較為完整地展現了其虔敬神學思想的整體圖景。在經歷了智術師懷疑主義和相對主義的衝擊之後，古代城邦的諸神信仰逐漸暴露出其隱含的內在矛盾。柏拉圖通過對虔敬的三個定義的探討，逐步展現諸神信仰作為神話神學的內在困境，進而討論了諸神信仰作為政治神學的正當性問題；在此基礎上，柏拉圖提出作為「理型」的虔敬以克服神話神學和政治神學所面臨的困境，實現了古代信仰從儀式性的諸神信仰到與靈魂緊密相連的理型之虔敬的轉變，初步確立了虔敬與那個「一」的關係。柏拉圖的這一神學轉向深刻影響著普羅提諾，並進而影響奥古斯丁的神學思想。

Piety is the core idea of Plato’s theology. Euthyphro whose subject is piety reveals this thought in depth. For the influence of Sophists’ skepticism and relativism, the belief of gods in ancient Greek exposed gradually its inherent contradiction. This paper suggests: through the interpretations of three definitions of piety, Plato revealed the difficult problem of the ancient belief as mythological theology and its rationality as political theology. Then Plato suggested the piety as εἶδος in order to avoid the contradiction and achieved the turn of ancient belief from the rite belief of gods to the εἶδος of piety which connected with souls. The theological turn of Plato established the relationship between piety and the One, and had profound influence on Plotinus and Augustine.