Believe me, if you now, contrary to all the better principles of your life, give the reins to your passions, the consequences may be such as you will rue for your lifetime, and even, if Heaven have not mercy, rue after your life is finished.
-- Sir Walter Scott, The Waverley novels, Volume 21
But he was also left to rue a brief spell before and after half-time when Cherries surrendered the lead by conceding twice in the space of three minutes.
-- Neil Perret, "Cherries: Great comeback but Howe left with mixed feelings," Bournemouth Echo, September 2010.
Rue descends from the Middle English ruen and shares the same root as ruth, compassion or pity.