An eagle was soaring through the air when suddenly it heard the whizz of an arrow, and felt itself wounded unto death.
Slowly it fluttered down to earth, with its lifeblood pouring out of it.
Looking down upon the arrow with which it had been pierced, it found that the haft of the arrow had been feathered with one of its own plumes.
"Alas!" it cried as it died.
"We often give our enemies the means of our own destruction."
From Aesop's Fables, Joseph Jacobs, ed by Charles W. Eliot c. 1937