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
Robert H. Schuller (1993). “Robert H Schuller: The Inspirational Writings : Tough Times Never Last, But Tough People Do/Tough Minded Faith for Tender Hearted People”, Bbs Publishing Corporation