How would I sum up the “essence of Christianity”? And how would I “position” my answer in relation to the two well-known books by that title by Ludwig Feuerbach and Adolph von Harnack?

I don’t believe I’ve given ten seconds thought to these authors since my graduate student days at Harvard, back when I was obliged to read such nonsense! But now that you ask I suppose I would say that I’m considerably, though of course paradoxically, closer to the atheist than to the liberal—or at least to this atheist and this liberal. The “fatherhood of God and brotherhood of man”, Harnack’s jejune distillation, misses the point completely, reducing religion to moral platitude, whereas Feuerbach’s famous sneer—that “theology is anthropology”—merely gets things backwards: anthropology is theology, man being “a creature under orders to be God”, in the words of Saint Basil.

One answer I might give to your question—I don’t say it’s the best—would be to cite the précis I provide my university students about half way through their course in Christian Theology. The academic term just ended last week, and I gave the graduate students the task of explaining this summary on their final examination:

We’ve learned in this course that a transcendent and yet immanent Mystery, than which nothing greater can be thought, whose center is everywhere and circumference nowhere, is (even as we speak) emptying Itself into our world and ourselves, at once (1) creatively and (2) re-creatively, bringing us and all things into existence from the No-Thing It is while at the same time redeeming and restoring those who, inevitably and yet reprehensibly, are falling away into a nothing It is not.

Now it is up to those who are falling away to respond, and this they do in two ways: (1) through their faith that the world-restoring operations of the Mystery have already achieved their goal; (2) through their recognition that, paradoxically, they are nonetheless responsible for achieving this very goal for themselves, which they can do by mirroring the operations of the Mystery, willingly emptying themselves into It even as It empties Itself into them, in order that finally they might become what It is.

As I’m sure you can see, Irenaeus, Origen, Athanasius, Gregory of Nyssa, Dionysius the Areopagite, Maximos the Confessor, John Scotus Eriugena, Bonaventure, and Meister Eckhart—among others—are embedded in these paragraphs, and it was up to the students to ferret them out and exposit the relevant principles.

Might there be an even more essentialized formulation of Christian doctrine? You tell me.