THE WOLF AND THE DOG IN PURSUIT

Perry's Index to the Aesopica

Fables exist in many versions; here is one version in English:

THE WOLF AND THE DOG IN PURSUIT

As he chased after a wolf, the dog capered with pleasure at how quickly he was able to run, revelling in his own strength. In fact, the dog actually imagined that the wolf was running away from him because of his superior prowess. But then the wolf turned around and said to the dog, 'I am not running away from you! I'm just afraid of being chased down by your master.'
The fable shows that you should not take pride in the good qualities that actually belong to someone else.

Source: Aesop's Fables. A new translation by Laura Gibbs. Oxford University Press (World's Classics): Oxford, 2002.
NOTE: New cover, with new ISBN, published in 2008; contents of book unchanged.

Perry 407: Gibbs (Oxford) 232 [English]
Perry 407: Syntipas 38 [Greek]

You can find a compilation of Perry's index to the Aesopica in the gigantic appendix to his edition of Babrius and Phaedrus for the Loeb Classical Library (Harvard University Press: Cambridge, 1965). This book is an absolute must for anyone interested in the Aesopic fable tradition. Invaluable.