I've never been big into Brahms but I bought this cassette back in the nineties as I had so enjoyed Thijs Van Leer's version of part of the third symphony (poco allegretto) on his 1988 album Reflections. Sadly the rest of the third symphony seems to me not quite so good as that section. What clinched it for me to buy this particular presentation was the addition of Brahms' Variations on a theme of Haydn. This is the piece that Focus adapted for the opening section of their magnum opus Hamburger Concerto. (See here) When I was in Secondary School the music teacher Mr Measey used to play some classical piece as we marched out of morning assembly. Most of it was lost on me but I remember one glorious morning when he played the Brahms variations. It's a great piece.
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.