Great article from Eighth Day Institute.
NOT MANY readers of C. S. Lewis know that, despite his well-known sympathies with the major texts and theologians of the West, he embraced a radically Eastern vision of the Christian life as a pilgrimage toward total transformation called theosis. This is a Greek word that does not actually appear in the New Testament. Yet like Trinity and Atonement, as terms also absent from Scripture, it is crucial for comprehending the Gospel. Roughly translated, it means the “divinizing” or “deification” of human life. C. S. Lewis’s friend Charles Williams gave it an odd English translation: “in-Godding.” We are called not merely to be yanked back from the brink of Hell, so that we remain ransomed but still sodden sinners for the sake of the Kingdom. Nor are we meant to follow Jesus as our Exemplar, striving for moral improvement so as to become “good people.” Important though these things surely are, they don’t touch the depths of theosis, which calls us to participate in the very life of God. We are summoned to be nothing other than icons of Christ. . . .
As Lewis also argues in Mere Christianity, the whole purpose of the Gospel is to turn Christians into what he variously calls “new men [and women],” “little Christs,” “Sons [and Daughters] of God”—all of which may rightly be called true icons.