We've been away this week as a family in Muston near Grantham on the borders of Leicestershire and Lincoln. We got to see Grantham itself, where Isaac Newton went to school and the farm (Woolsthorpe Manor) where he was born and had some of his great ideas. We also got to see a bit of Sherwood Forest, a windmill in Tuxford (briefly) and the lovely mediaeval town of Stamford (not pictured).
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.