David Copperfield ch. 28 (1850). The Oxford Dictionary of Proverbs cites Peter Atall, Hermit in America (1819): "Accidents will happen in the best regulated families." See Robert Burns 3; Disraeli 7; Modern Proverbs 102; Orwell 17; Plautus 3; Proverbs 2; Sayings 25
F. Scott Fitzgerald (2015). “Babylon Revisited and Other Stories (Fitzgerald’s Greatest Short Stories): A Collection of short stories from the author of The Great Gatsby, The Side of Paradise, Tender Is the Night, The Beautiful and Damned, The Curious Case of Benjamin Button and many other notable works”, p.185, e-artnow