Nasruddin did not want to loan him the donkey, but he also did not want to appear to be ungenerous. So, he made up an excuse.
"I'm sorry, but I must say no," said Nasruddin. "The donkey is not here right now; I loaned him to my brother-in-law, and he still hasn't returned the donkey."
Then, at that very moment, the donkey let out a loud bray from inside the stable.
Before his neighbor could say anything, Nasruddin gave him a hard look. "Who are you going to believe: me, or the donkey?"
Inspired by: 202 Jokes of Nasreddin Hodja by Her Hakki Mahfuzdur
Notes: This is story 8 in the book. In some versions of this story, Nasruddin goes on to add that anyone who would take the word of a donkey is not worthy of any kind of loan. Compare a similar rooster story: The Rooster's Tail-Feathers.