Ye are the salt of the earth: but and if the salt be once unsavory, what can be salted there with? It is thence forth good for nothing, but to be cast out at the doors, and that men tread it under feet.
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.