Aesop's Fables (1884)
88. The Dogs and the Fox.
Some Dogs, finding the skin of a lion, began to tear it in pieces with their teeth. A Fox, seeing them, said: "If this lion were alive, you would soon find out that his claws were stronger than your teeth."
It is easy to kick a man that is down.
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.