I've spent the last couple of days in Oxford looking out the Beddome archive at the Angus Library in Regents park College. It is easy enough to get a coach to Oxford from Baker Street and be in Oxford in about 90 minutes. I've done it before. This time I popped into Lincoln College where I once spent a night many years ago exploring being a student there. I hope to get there again soon.
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.