The quote is from Pascal: "Je n'ai fait celle-ci plus longue que parce que je n'ai pas eu le loisir de la faire plus courte", "I made this one [the letter] longer, since I didn't have the leisure to make it shorter".
> If it is a ten-minute speech it takes me all of two weeks to prepare it; if it is a half-hour speech it takes me a week; if I can talk as long as I want to it requires no preparation at all. I am ready now.
~ Woodrow Wilson, as quoted in The Operative Miller 23