Alfred Nock on the central fact of Jesus' teaching

From Alfred Nock's brilliant (if somewhat old) book, Conversion: The Old and the New in Religion from Alexander the Great to Augustine of Hippo. (Oxford U Press 1933)

“The central fact in the teaching of Jesus was not a novel doctrine about God or man but the heralding of the kingdom. It was not new: it had been in many Jewish // minds for a century and more: it had been urged with compelling force by John the Baptist.” (pp 242, 243)

I also liked this one:

“Celsus…speaks of Christian rites as performed in cobblers’ shops or fullers’ shops.” (p 202)

In this book he tries to narrow down just exactly what was new in Christianity? Was it the Kingdom of God? (No.) Was it the sacraments? (No.) Was it the incarnation? (Uh, sort of.) Was it vicarious atonement? (Yes.) And so on...