Source, in full
Order of the Day during the Battle of Verdun (23 June 1916), quoted in Alistair Horne, The Price of Glory: Verdun 1916 (1962, 1993), p. 231 and Ian Ousby, The Road to Verdun: France, Nationalism and the First World War (2002), p. 231
Attribution
Quote text and notes from Wikiquote: Robert Nivelle (page history), available under CC BY-SA 4.0. Source quality and labels are our own summary of what Wikiquote records.