On 31 October 2001, Professor Michael Welker delivered the Horace De Y. Lentz Memorial Lecture at the Harvard Divinity School. The founding bequest of the triennial lectureship specifies that “some outstanding Christian priest, minister or layman” should speak “upon the inspiring things he may discern in the words: ‘Christo et Ecclesiae’ which appear upon the Harvard Seal.” An edited transcript of Professor Welker's lecture follows.*The author is grateful to Dr. John Hoffmeyer for translating this lecture, and to Dr. Gene McGarry for his editorial assistance.