“Don’t be afraid of the dog, “said the lady to Little Johnny, who was delivering her groceries.
“You know the old proverb, ‘A barking dog never bites?’“
“Yes, “replied Little Johnny. “You know the proverb. I know the proverb. But does your dog know the proverb?”
This joke is included in the Black Book of Jokes. You can order it from here.