I picked up Ian Hamilton's little book The faith shaped life at the Banner. I think I mentioned recently that I like to read books by people I know. I had mistakenly thought it was a series of studies on faith but it is, in fact, a collection of 43 "pastoral letters" written over the years. (I think you can find them on his church's website - here). I'm not sure why the book lacks a little foreword explaining this. It is an important part of the pastor's duties in some traditions (Ian would be very much a Willie Still man, a selection of whose letters was published by Banner some years ago). My old pastor used to do it. Anyway, this book is a fine read. There are rare repetitions but lots of good quotations and sensible points in brief compass.
Bonhoeffer uses a similar phrase 'worldly Christianity'. It's J Gresham Machen that I want to line up most closely with. See his Christianity and culture here. Having done commentaries on Proverbs (Heavenly Wisdom) and Song of Songs (Heavenly Love), a matching title for Ecclesiastes would be Heavenly Worldliness. For my stance on worldliness, see 3 posts here.