Theosis

Theosis, also called deification or divinization, is a central concept in Christian theology describing the process by which humans are transformed through God's grace to participate in the divine life. It does not imply that creatures become God by nature; rather, humans become participants in God's life while remaining creaturely.

In Eastern Orthodox theology, theosis is the ultimate goal of salvation. It is pursued through baptism, participation in the Eucharist and other sacraments, prayer, fasting, and ascetic struggle, under the renewing work of the Holy Spirit. Theologians distinguish between God's essence and His energies to explain how creatures may experience deification without becoming identical to God. Through grace, believers are transformed in love, joined to Christ, and increasingly united with God in this life and perfected in the eschaton.

Historically, the idea appears in patristic writers such as Irenaeus and Athanasius, with later development in the Eastern tradition, notably Gregory Palamas, who articulated the essence-energies distinction and the Hesychast emphasis on contemplative prayer as a vehicle of theosis. The phrase "God became man, so that man might become God" is associated with Athanasius to summarize the saving purpose of the Incarnation.

In Western Christianity, the concept exists as divinization or deification, though it is less central. Catholic and Protestant writers speak of the transformative grace by which believers share in the divine life, while keeping God’s transcendence and the created nature of humanity. Theosis remains a foundational lens for understanding salvation as communion with God rather than moral improvement alone.