A Minyan in Hebron
There were very few Jews in Hebron several centuries ago, and the only way they were able to have a minyan for Shabbat and Holiday services was through the arrival of some Jews from the surrounding villages. One year those Jews decided to go to Jerusalem for Yom Kippur, and the Hebron community was left with only nine men, with no tenth man in sight to complete the minyan for services.
As they wept over the likelihood of Yom Kippur without a minyan, an aged stranger appeared. He refused their offer of a pre-fast meal saying that he had already eaten one during his travel. After a very special day of prayer, one of the community leaders invited the mysterious stranger to his home to break the fast. When they reached the house, however, the guest suddenly disappeared. After a futile search the disappointed host had a somewhat restless sleep during which the stranger appeared to him in a dream. He identified himself as the Patriarch Avraham, who saw how pained they were and joined them for one day as the tenth man in the city where he lived and was buried.