We were a good number last Wednesday as we tackled the next of the five solas - this time sola fide, by faith alone. It is a basic doctrine but it was good to go over it again, especially the emphases rediscovered in the Reformation. I found Tom Schreiner's book on the subject very helpful. We had a good prayer session.
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.