I struggled with a bad cold all last week. (I think may be you cope less well with these things as you get older). Anyway this made preparation difficult but we got there and things mostly went okay, except for a coughing problem in the evening that forced me to ask one of the students to come up and read (thankfully he was the only one to choose from as the others were preaching elsewhere). I think that's only ever happened once before. (I had my son Rhodri to read that time). Anyway I decided to take a text in the morning - Hebrews 2:3. It was good to focus on one verse. It preached quite differently to how I imagined it and included a biblical theology of salvation that people appreciated. Sermon here. We then had lunch together which was great. I enjoyed discussing some offbeat theories of the cross and the moon landings with two Nigerian sisters in the congregation. In the evening I was quite short and we were again low in numbers. A lady across the road managed to miss both morning and evening services but arrived for lunch and to give a hearty Amen to the benediction.
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.