At the end of each one he would throw the foreskins into a jar in his bag.
After many year he had gathered a rather large collection of foreskins.
Unsure of what to do with them he consulted his friend, the leatherworker.
The leatherworker tells him he has an idea and he will call the rabbi in a few weeks.
One day the rabbis phone rings and the leatherworker tells him to come by his shop.
Upon his arrival, the leatherworker hands the rabbi a wallet.
The rabbi says,”All those foreskins and all you have made is a wallet?”
The leatherworker replies,” If you rub it, it turns in to a briefcase.”