The weakest of all weak things is a virtue which has not been tested in the fire.
(Mark Twain [Samuel Langhorne Clemens] (1835-1910), U.S. author. 1899. The aggrieved stranger, in "The Man That Corrupted Hadleyburg," p. 426, Mark Twain: Collected Tales, Sketches, Speeches, & Essays, 1891-1910, Library of America (1992).)
Many writers are neither spirit nor wine, but rather spirits- of-wine: they can catch fire, and then they give off heat.
(Friedrich Nietzsche (1844-1900), German philosopher, classical scholar, critic of culture. Friedrich Nietzsche, Sämtliche Werke: Kritische Studienausgabe, vol. 2, p. 597, eds. Giorgio Colli and Mazzino Montinari, Berlin, de Gruyter (1980). The Wanderer and His Shadow, aphorism 101, "Spirits-of-Wine Authors," (1880).)
"Heap coals of fire on the head of your enemy" Mthis most uncharitable advice is found in a book [the Bible], of which charity is reckoned the standard principle.
(Horace Walpole (1717-1797), British author. Horace Walpole's Miscellany 1786-1795, p. 64, ed. Lars E. Troide, Yale University Press (1978).
Originally written in 1787; Walpole, a deist, was skeptical towards the Bible as a repository of divine wisdom.)