Your race, in its poverty, has unquestionably one really effective weapon — laughter. Power, Money, Persuasion, Supplication, Persecution — these can lift at a colossal humbug, — push it a little — crowd it a little — weaken it a little, century by century: but only Laughter can blow it to rags and atoms at a blast. Against the assault of Laughter nothing can stand. You are always fussing and fighting with your other weapons. Do you ever use that one? No; you leave it lying rusting. As a race, do you ever use it at all? No; you lack sense and the courage.

Mark Twain (1835-1910) American writer [pseud. of Samuel Clemens]

“The Chronicle of Young Satan” (c.1897–1900, unfinished)
    (Source)

Often paraphrased: "The human race has one really effective weapon, and that is laughter." This is an excised passage from what was eventually posthumously published as No. 44, The Mysterious Stranger (1916).