This article examines the outlines of the epistemological theories of Aristotle and Gregory Nazianzen, which emphasized active, practical and embodied aspects of the process of intellection. It also investigates the notion of medium and the principle of likeness as the key-components of the epistemological thoughts of the both authors. Although the idea of inherent likeness tying together the agents of intellectual process (the subject and object of thought) was known since the Atomists and widely supported by Plato and other philosophers, it lied with Aristotle to identify the significance of thinking as active and embodied practice, which requires cooperation between the agents. Gregory transformed this “contact” theory of epistemology into a Christian understanding of theological thinking. Gregory also used Pauline idea of likeness and cooperation between men and God manifested in the pursuit of theological knowledge. Maximus the Confessor explained and elaborated Nazianzen’s epistemological thoughts through Aristotelian doctrine. Analysis of direct and indirect continuities between the theological and philosophical approaches to knowledge and the process of thinking shows that Christian creative reception involved not only re-thinking Hellenic philosophical terminology but also adjusting philosophical view of knowledge to the Christian theory and practice.