I think sermons do get recycled and borrowed. In a chuch I visited twice, both sermons were very similiar to ones I had heard years ago at a different church. I think that there are books out there of ideas for sermons.

I think there are fad catch phrases in Christianity. I see them on T shirts, book bags, plastic wrist bracelets, etc. There are slogans like "What would Jesus do?" and "Got Jesus?" So this might have been a catch phrase of the time.