The term ‘Kingdom of God’ occupies a theologically dense and psychologically generative position within the depth-psychology corpus. Across patristic, mystical, and depth-psychological texts alike, it functions less as a political or future-tense eschatological promise than as an interior, present-tense reality accessible through purification, prayer, and contemplative transformation. The Philokalia traditions — drawn principally through Maximos the Confessor, Gregory Palamas, and allied Hesychast writers — insist with remarkable consistency on the Lukan formula ‘the kingdom of God is within you,’ anchoring the concept firmly in the interior life rather than in external or historical expectation. John Cassian offers a characteristically monastic reading, counterposing the kingdom of God against the kingdom of the devil as the twin outcomes of virtue and sin respectively. John of Damascus develops a sophisticated theology of the kingdom’s eschatological delivery from Son to Father, resisting any reading that diminishes either person’s sovereignty. Rudolf Otto situates the kingdom within the phenomenology of redemption as Christianity’s supreme salvific promise. Alexander Schmemann, read through Andrew Louth, reclaims the eschatological tension — the kingdom as both historical event and its transcendence. The Philokalia volumes distinguish ‘kingdom of heaven’ from ‘kingdom of God’ with metaphysical precision, locating the former in the consummation of created things and the latter in the deifying impartation of divine grace. This inward turn, constant across the corpus, makes the term a touchstone for the psychology of transformation.