I have made it my practice over the last few years to begin the year with a motto text. This ear it is Romans 13:12. An mp3 will soon be on the church website and the text of the sermon can be found here on preached sermons.
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.