Derek Thomas has written an excellent little book on that vital chapter Romans 8. These were originally sermons but they have been lightly re-edited for reading and cover the ground in a most readable and spiritually nourishing way. With quotes from Calvin, Owen, some of our great hymns and other excellent sources the book moves through the material a few verses at a time with confidence and clarity in a way that any Christian could benefit from. I read my copy on kindle but the book is available in other formats. The book is called How the gospel brings us all the way home.
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.