A man walks down the street and suddenly notices his watch has stopped working.
He looks around looking for a watch shop nearby. At the end of the street he sees a small store with a big clock hanging outside and he goes over there. When he enteres the store, to his surprise he does not see a display of watches, but only a long counter, behind it sits a Jewish rabbi with a long white beard.
“Hello,” the man says, “Can you please check my watch, I think it broke down.”
“I’m sorry,” the seller says “I do not know anything about watches. I am a mohel. I perform circumcisions”.
“How nice,” the man answers “definitely important work.” He continues. “But if so, why did you hang a large clock outside your store?”
“Well,” replies the mohel “What do you expect me to hang out there?”