Rabbi Akiva was once walking along a deserted road when he met a ghostly figure — a man pale as smoke, staggering under a load of firewood he had cut himself.
"Who are you?" Akiva asked. "And where do you go with this wood?"
"I was once a man," the figure said. "I died a sinner. Every day I am forced to gather these sticks and carry them to the place where I am burned in Gehinnom."
Akiva's heart turned. "Is there nothing I can do to help you?"
"Only one thing," the man whispered. "I left a son behind in the world above. Find him. Teach him Torah until he can stand in the synagogue and lead the community in the Kaddish and the blessings. When my son recites the Barchu before a congregation and the people answer him — 'Blessed is the Lord forever' — my punishment will end. A father whose son sanctifies God's name in public is no longer alone in the fire."
Akiva took the charge. He sought out the boy, who had been left an orphan and untaught. He fed him, clothed him, taught him to read Hebrew, taught him the prayers, taught him Torah — until the day came when the son stood at the amud in the synagogue and called out, "Barchu et Adonai ha-mevorach — Bless the Lord who is to be blessed." The congregation answered. That same night, in a dream, the father appeared to Akiva clothed in light. "You have saved me," he said.
The Exempla keeps this tale to teach that the obligation of a son to say Kaddish is no small custom — it is an act with consequences in both worlds — and that a Jewish community that adopts an orphan and teaches him to pray rescues more than one generation.
(From The Exempla of the Rabbis, Moses Gaster, 1924, no. 134, drawing on Kallah Rabbati 2.)