Eastern Orthodox soteriology centers on theosis (deification)—the genuine and ongoing participation of the human person in the divine life of the Trinity through union with Christ in the Holy Spirit. The classic formulation from St. Athanasius—'God became man so that man might become God'—captures the Orthodox vision: salvation is not merely the forgiveness of legal guilt but an ontological transformation of the human person through grace. This transformation begins in baptism, is nourished by the Eucharist and ascetic life, and reaches its fullness in the eternal Kingdom.

Synergism is essential to Orthodox soteriology: salvation is a genuine cooperation between divine grace (which always takes the initiative) and human freedom (which freely responds and grows). The concept of theosis draws on 2 Peter 1:4 ('partakers of the divine nature') and is grounded in the Incarnation: because God united himself to human nature in Christ, human nature is now capable of participating in divine life. Orthodox soteriology also emphasizes the communal dimension of salvation: one is saved in and through the Church, the Body of Christ.