I took it to mean by adhering ( demanding obedience ) to custom/tradition, they're selling themselves short as their contribution to our identity is so much more profound - they should step on the gas and expand to envelop the new in lieu of resisting/attacking it. Don't counter, absorb and expand - e.g. own the wonder that arises from science, make it holy, allow it to contribute to identity, as counter/repressing science fuels it's destructiveness to what we are.
But I could be wrong.
Yeah, I think we are both heading in the same direction.
The quote itself is ensconced in a short chapter which is very obtuse (there are parts that have a footnote per sentence). The main thrust of it though is how the "Christian mind" approached the figure of God (and Christ) in Revelation. That is, what was the need for Revelation? So, in this way, he discusses the idea of the Antichrist as a reconciliation of the sort of dual-nature of God and so something of the dual-nature of Christ.
So, what he seems to be saying is that such a thing as Revelation, while understandable, didn't need to be a forgone conclusion. And still doesn't have to be. That is, it need not be, necessarily, Apocalyptic. Rather then see that house as having to be destroyed to be reborn, one could see that house appended.
If I understand it right, which is a massive if, because most of the chapter is highly opaque.