The Perennial Difficulty of Christ's Revelation
Found in the publication file for "Contemporary Readings in the Higher Sophistry" (America 70.13 (1944): 343-345). In response to a letter from a reader, Ong wrote:
This is the perennial difficulty of Christ's revelation: it is the most satisfactory thing we know, but to have it and keep it I must reform and keep reforming myself.
I've discussed Ong's theology and its role in his scholarship before, how he believed himself to be describing God's unfolding and ever-evolving creation rather than to develop a theory to defend, and I think we might regard this comment as the corollary to that.