This monograph offers a comparative study of Cyril of Alexandria (c.378–444) and Matta al-Miskīn (1919–2006) on humankind’s union with God, or deification, as articulated in their commentaries on the Gospel of John. By bridging over fifteen centuries, it highlights the continuity of contemporary Coptic Orthodox thought with its Alexandrian roots. Both theologians emphasise the real, existential, and transformative nature of divine participation. While this participation is substantial, not superficial, both Cyril and Matta underscore the profound asymmetry between the divine being (God) and the human participant, affirming the mystery of this union within the framework of Orthodox theology.