Aesop's Fables (1884)
102. The Partridge and the Fowler.
A Fowler caught a Partridge, and was about to kill him. The Partridge earnestly besought him to spare his life, saying: "Pray, master, permit me to live, and I will entice many Partridges to you in recompense for your mercy to me." The Fowler replied: "I shall now with the less scruple take your life, because you are willing to save it at the cost of betraying your friends and relations;" and without more ado he twisted his neck and put him in his bag with his other game.
Those who would sacrifice their friends to save themselves from harm are not entitled to mercy.
Aesop's Fables: A New Revised Version From Original Sources (translator not identified), 1884 . Illustrations by Ernest Henry Griset (1844-1907), John Tenniel (1820-1914) and Harrison Weir (1824-1906). Available online at Project Gutenberg.