Source for Klingon Proverb

Mullings An American Cyber Column By Rich Galen:

• Seven months later, when he had to fess up because he didn't want to be accused of lying to yet another grand jury, the Clintons were looking for friends.
• They did not find one in Joe Lieberman.
• Hillary Clinton returned the favor last week.
• 'Revenge,' as Pierre Ambroise Francois Choderios de LaClos wrote in his 1782 book Les Liasons Dangereuses, 'is a dish best eaten cold.'"