As we come to the rugby world cup semi-finals, there was a piece on the ITV News last night. They wanted to highlight Argentina's lowliness and chose to do so by noting that it has only 102790 registered layers compared with England's massive 1990988 (more than any other country). However, if you check on Wikipedia you will see that although South Africa and New Zealand the other semi-finalists are in the top five on this indicator, Australia who Argentina play against are down at 14th with only 42100 registered players (just behind Kenya) so it is not a helpful statistic. Wales, by the way, have 50557 registered players.
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.