Bit late with this because it's been so busy this week. Paul Levy complained somewhere because those he knows who report on their Sundays never seem to have bad ones. I know what he means but for me it's the week days that are bad not the Lord's days. So in the morning we began with communion and that was followed by a sermon on the closing verses of 1 Corinthians 4. My two main points were about "You and your fathers in Christ" and "The danger of arrogance in God's kingdom and how God deals with it". In the evening we came to the penultimate chapter of Numbers and thought about Christ and the cities of refuge.
The similar phrase 'Worldly Christianity' is one used by Bonhoeffer. 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.