I have only made this [letter] longer, because I have not had the time to make it shorter.

[Je n’ai fait celle-ci plus longue que parce que je n’ai pas eu le loisir de la faire plus courte.]

Blaise Pascal (1623-1662) French scientist and philosopher

Lettres provinciales, #16 (1657)

Alt. trans.: "The present letter is a very long one, simply because I had no leisure to make it shorter." Sometimes attributed to Ben Franklin or Mark Twain. For more information see here.