Religious and anthropological issues of the Eastern Patristics legacy are under consideration in the article. The conceptual justification of the human being by Greek-Byzantine Church Fathers is submitted, paying attention to antinomianism in understanding the Man essence. The human duality is analyzed in tight with the diversity of historical theologian approaches to clarifying the New Testament thesis on the creation of Man in the image and likeness of God. In this context, a doctrine of Irenaeus, a Church Father of the ante-Nicene period of Christianity, some ideas of a non-canonical Early Christian manuscript, The Shepherd by Hermes of Philippopolis, and teaching on Man by Gregory of Nyssa as one of the profound representatives of the Patristics’ classical period are presented. The author examines a notion of deification with specific stress on its religious and philosophical meanings. Deification is studied both as the theoretical foundation for the Eastern Christian anthropological tradition forming over the Middle Ages and as the religious gnosis, purifying, perfecting, and transfiguring of a human being on their God knowing ascending path. Deification is deduced as a peculiar style of life that aims at the eschatological and soteriological prospects of human existence, which are correlated with the highest religious morality and eternal desire to reach the cherished spiritual state of God and Man union. In this regard, the doctrine of a follower of allegorical theology, Maximus the Confessor on the Logoi, or God’s energies, is very significant as well as his interpretation of the notion of deification. According to St. Maximus, the comprehension of Logoi by the human being supports the unification of the mundane world with the Creator (the omnipotent Logos). It means the deification of the entire humanity. The article is based on the texts of Church Fathers, which are the sacred primary sources of Christianity. © 2022 Saint Petersburg State University. All rights reserved.