If interested in learning the basis of the claim, here is a little bit more from the text:
“In their own ways, Marx, Freud, Feuerbach, and Sartre all maintain that God must be eliminated if humans are to be fully themselves. But there is none of this in the Christian doctrine of the Incarnation. The Word does indeed become human, but nothing of the human is destroyed in the process; God does indeed enter into his creation, but the world is thereby enhanced and elevated. The God capable of incarnation is not a competitive supreme being but rather, in the words of Saint Thomas Aquinas, the sheer act of being itself, that which grounds and sustains all of creation, the way a singer sustains a song.
And the Incarnation tells us the most important truth about ourselves: we are destined for divinization. The church fathers never tired of repeating this phrase as a sort of summary of Christian belief: Deus fit homo ut homo fieret Deus (God became human so that humans might become God). God condescended to enter into human flesh so that our flesh might partake of the divine life, that we might participate in the love that holds the Father, Son, and Holy Spirit in communion. And this is why Christianity is the greatest humanism that has ever appeared, indeed that could appear. No philosophical or political or religious program in history—neither Greek nor Renaissance nor Marxist humanism—has ever made a claim about human destiny as extravagant as Christianity's. We are called not simply to moral perfection or artistic self-expression or economic liberation but to what the Eastern fathers called theiosis, transformation into God.”
