As far as I recall I've never been to a December wedding. I am aware that they take place but somehow this year they are suddenly all the rage it seems. I know of people getting married on the 3rd, 10th and 17th and one even nearer to Christmas day. I am only going to one (my son's) but here;s wishing you all a really good day as it fast approaches. Hope it's not too cold (one is in South Africa so it's not likely to be).
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.