Address at the Sorbonne, Paris, 23 Apr. 1910. Richard M. Nixon quoted this passage in his address to the nation announcing his decision to resign the presidency, 8 Aug. 1974. See Theodore Roosevelt 1; Theodore Roosevelt 2; Theodore Roosevelt 5
"Incredible Quotations: 230 Thought-Provoking Quotes with Prompts to Spark Students' Writing, Thinking, and Discussion". Book by Jacqueline Sweeney, 1997.