“The present letter is a very long one, simply because I had no leisure to make it shorter.”
Pascal humorously links brevity with revision time: concise expression can require more deliberate work than writing at length under pressure.
Source details
The Provincial Letters, Letter XVI, dated December 4, 1656, Project Gutenberg #73959. Pascal apologizes for the unusual length and rapid succession of his letters, saying the present one is long because he had no leisure to make it shorter. The sentence belongs to translated seventeenth-century religious polemic and is a witty observation about composition, not a measured productivity law.