The Or Zarua (Rav Yishak of Vienna, 13th century) brings a Midrash that tells a remarkable story about Rabbi Akiba, who once saw a man running frantically while carrying a large stack of twigs. The man was unclothed, and his body was black like charcoal.
Rabbi Akiba asked the man to stop, and offered to help. He assumed that this man was a slave working for a ruthless master, and he wanted to release him from his state of servitude so he would not have to continue suffering.
The man explained to Rabbi Akiba that he actually was not from the world of the living. When he was alive, he worked as a tax collector, and he would heartlessly tax the needy into poverty while currying favor with the rich, among other grave misdeeds. His punishment was that he needed to collect firewood every day, to be then burned in the fire. The only chance to end this suffering, the man told Rabbi Akiba, was for his son to recite Kaddish or lead the recitation of Barechu in the synagogue. He had died when his wife was pregnant with their only child.
Rabbi Akiba asked the man about his wife's name and place of residence, and he went to find this man's child. When he asked the townspeople about the widow and her child, they angrily cursed the deceased man who was so cruel and heartless, driving many people to destitution. Rabbi Akiba learned that the man had a son, but he was not even circumcised, and certainly never learned Torah such that he would be in a position to recite Kaddish.
After finding the young man, Rabbi Akiba convinced him to have a berit mila. He tried teaching him Torah, but the young man had extreme difficulty learning. Rabbi Akiba fasted for forty days, beseeching G-d to help the boy learn. He was then able to teach him. Eventually, when the young man was ready, Rabbi Akiba brought him to the synagogue, and he recited Kaddish and Barechu. Rabbi Akiba continued teaching this young man Torah, until he emerged as a great scholar, known as Rabbi Nahum Ha'pakoli. The name "Ha'pakoli" alludes to the verse in the Book of Yeshayahu (28:7), "Paku Peliliya" – "He who extracts the guilty," which is precisely what Rabbi Nahum did, rescuing his sinful father from eternal suffering.
The father appeared Rabbi Akiba in a dream and wished him that he be granted a distinguished place in Gan Eden. He explained that after his son recited Kaddish and Barechu, he was relieved of the suffering that had been decreed. When the son began learning Torah regularly, he was no longer subject to any punishment. And when the son was ordained as a Rabbi, he was brought to Gan Eden to join the Sadikim.
This is an early source of the time-honored custom to recite Kaddish on behalf of one's deceased parent, which has the effect of sparing the parent from punishments in the afterlife.
Another source is a passage in Tanna De'beh Eliyahu, brought by Rabbi Eliezer of Worms (Germany, d. 1238), which states that even a small child can save his father from the punishments of Gehinam through the recitation of Kaddish.
Moreover, the Yad Eliyahu writes that by reciting Kaddish for a deceased parent, one fulfills the Misva of Kibbud Ab Va'em – honoring one's parent. In fact, the Yad Eliyahu adds, one has more of an opportunity to fulfill the Misva of Kibbud Ab Va'em after a parent's passing, since during the parent's lifetime, the parent can decline the child's offers to give honor. After the parent's passing, however, the parent cannot refuse the recitation of Kaddish – and even if the parent never requested that Kaddish be recited after his or her death, the child must assume that this was the parent's wish. As Kibbud Ab Va'em constitutes a Torah obligation, we follow the rule that one must act stringently in situations of uncertainty ("Safek De'Orayta Le'humra"), and thus a child must, under all circumstances, recite Kaddish for a deceased parent.
Similarly, Rav Yosef Engel (1858-1919) writes that reciting Kaddish is the highest form of Kibbud Ab Va'em, as there is nothing greater that one can do for a parent than bring the parent to Gan Eden, which is what a child achieves by reciting Kaddish.
Our community can be proud that this practice is meticulously observed, virtually without exception. Even when people travel, if they are in the first year after a parent's passing, Heaven forbid, they ensure to have a Minyan available so as not to miss even a single recitation of Kaddish. This is a testament to our community's awareness of the great importance of this cherished custom, and of our community's strong dedication to the precious Misva of Kibbud Ab Va'em.
Importantly, however, Hacham Ovadia cites the Yosef Ometz as noting that the Kaddish recitation was instituted for those who are unable to benefit their parents' souls through the study of Torah. The benefit brought through Torah study is many times greater than the recitation of Kaddish, and if one arrives at a Hiddush (a novel Torah insight) while learning in his parent's memory, he brings immeasurable honor to the parent's soul in the afterlife. Therefore, as important as it of course is to recite Kaddish for a deceased parent, it is even more important to devote time to learn Torah in the parent's memory, as this is the greatest thing one can do for a deceased parent's soul.
Many parents, understandably, are troubled by the exorbitant cost of Torah education. However, while the problem is real, and should be addressed, at the same time, we must maintain a proper perspective and realize that no matter how much money parents pay for their children to receive a Torah education, the dividends are infinitely greater. There is no price tag that one can place on eternal life in Gan Eden, and being spared the punishments of Gehinam. By providing their children with a proper religious education, parents ensure that their children will recite Kaddish and learn Torah in their memory, thereby guaranteeing their place in Gan Eden for all eternity – and we can all agree that there is no price too high for that.