I was in Dunstable Baptist Church on Sunday. I'd never been there before and was encouraged to see such a large and diverse congregation. I know a few of the folk a little and enjoyed lunch with David Green from LTS and his family. I preached evangelistically (end of Matthew 11) in the morning and we looked at 1 Corinthians 8 in the evening. Before leaving I got to look at the Strict Baptist Historical Society Library which is on the premises and is an excellent resource. The church also has a bookshop at the back. It was a good day. Back here they were very busy I understand with good congregations.
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.