Focus on Man Proposes, God Disposes and discuss the Origin of the title.
The phrase "Man proposes, but God disposes" is a translation of the Latin phrase "Homo proponit, sed Deus disponit" from Book I, chapter 19, of The Imitation of Christ, a 15th-century book by the German cleric Thomas à Kempis. A few modernized and paraphrased Bible translations use it as a translation of Proverbs 19:21, but the original of that verse is longer and more elaborate.
The phrase was also put on a Dutch commemorative medal celebrating the Elizabethan England Protestant victory in 1588 over the Catholic Spanish Armada.
A similar phrase appears in the concluding lines of Lucian's "Symposium" (circa 150 AD), quoting from the concluding lines of Euripides's Alcestis, Andromache, Helen, and Bacchae (5th century BC): "πολλὰ δ᾽ ἀέλπτως κραίνουσι θεοί" (loosely translated, "the gods bring many matters to surprising ends").
Lucian The Imitation of Christ Thomas à Kempis Spanish Armada Bacchae Euripides Andromache Alcestis Helen