I'm planning to be at the John Owen Centre today where the Theological Study Group will be discussing George Smeaton's book Christ's Doctrine of the atonement. It's been good to read a book that has sat on my shelf unused too long. It is full of excellent insights.
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.