“There is nothing that sharpens a man's senses so acutely as to know that bitter and determined enemies are in pursuit of him night and day.”

Source: Sense and Sensibility

Source: Turn Coat

Tel Quel (1943)

The Rickover Effect (1992)
Context: Nothing so sharpens the thought process as writing down one's arguments. Weaknesses overlooked in oral discussion become painfully obvious on the written page.

Observer (20 January 1927).

1850s, Address before the Wisconsin State Agricultural Society (1859)
Context: I suppose, however, I shall not be mistaken, in assuming as a fact, that the people of Wisconsin prefer free labor, with its natural companion, education. This leads to the further reflection, that no other human occupation opens so wide a field for the profitable and agreeable combination of labor with cultivated thought, as agriculture. I know of nothing so pleasant to the mind, as the discovery of anything which is at once new and valuable — nothing which so lightens and sweetens toil, as the hopeful pursuit of such discovery. And how vast, and how varied a field is agriculture, for such discovery. The mind, already trained to thought, in the country school, or higher school, cannot fail to find there an exhaustless source of profitable enjoyment.

Source: “Big Business and the Rise of American Statism,” 1969, p. 23

Source: A Midsummer Night's Dream

Quoted in V. Ye. Savkin, "Basic Principles of Operational Art and Tactics," 1972.