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 culturehere. 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.
Where have I been?
I took both these pictures in the same city where I went on a road trip with my second son (Dylan) this week, while the rest of the family enjoyed Alton Towers. Can you guess where? More to follow.