Of this most supremely Divine blessedness — exalted beyond all, the threefold Monad, the really Being, — the Will, inscrutable to us, but known to Itself, is the rational preservation of beings amongst us and above us; but that (preservation) cannot otherwise take place, except those who are, being saved are being deified. Now the assimilation to, and union with, God, as far as attainable, is deification.

[T]he redeeming work of Christ — or rather, more generally speaking, the Incarnation of the Word — is seen as directly related to the ultimate goal of creatures: to know union with God. If this union has been accomplished in the divine person of the Son, who is God become man, it is necessary that each human person should in turn become god by grace, or become “a partaker of the divine nature,” according to St. Peter’s expression (2Pe.1:4).