Jan Blahoslav (1523 – 1571) was a Czech humanist writer, poet, translator, etymologist, hymnographer, grammarian, music theorist and composer. He was a Unity of the Brethren bishop. He translated the New Testament from Greek into Czech in 1568. This was incorporated into the Bible of Kralice (1588). Born in Přerov, Moravia, he studied theory under Listenius and Hermann Finck at Wittenberg from 1544. There he got to know Luther and Melanchthon. After a short period at Mladá Boleslav (1548, 49) he continued his education at Königsberg and Basle. He was a fine linguist who strove to preserve the purity of his native tongue. He was ordained at Mladá Boleslav, 1553 and became a bishop, 1557. In the following year he established himself at Ivančice, where before long he installed a printing press. Towards the end of his life he moved to Moravský Krumlov, where he died, aged 49. He wrote what is believed to be the first book on music theory in the Czech language in 1558. It is derivative, using the writings of Listenius, Finck, Ornithoparchus and Coclico but Blahoslav wrote two entirely new sections for the second edition giving critical and practical advice to singers and choirmasters, and guidance to hymn composers. He was the chief editor of the Pisně duchowni ewangelistské (1561), known as the Szamotuły Kancionál, which contains 735 hymn texts, 52 by Blahoslav, and more than 450 tunes, including a number drawn from secular sources and eight which he may have composed himself. He has been greatly esteemed for his translation of the New Testament. His work influenced Jan Amos Komenský.
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.