John Henry Newton (1725 – 1807) was a British sailor who became an Anglican minister after his powerfulconversion while still at sea. He started his career at sea at a young age and was involved with the slave trade for some years. He himself was also enslaved for a period. He is remembered today chiefly as a preacher, writer abolitionist and the author of many hymns, including Amazing Grace. Do check out the John Newton project here.
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.