Theosis, also called deification or divinization, is participation by grace in the life of God. It is a central expression of salvation in Eastern Christian theology.
Meaning
Human beings do not become divine by nature or cease to be creatures. Through union with Christ and the indwelling Holy Spirit, they are healed, transformed, and made “partakers of the divine nature” (2 Peter 1:4).
Life in Christ
Theosis begins in this life through baptism, Eucharist, prayer, repentance, ascetic struggle, charity, and growth in holiness. It is possible because the Son of God truly assumed human nature, died, rose, and ascended in glory.