The worst of the evil will return not only to the one who committed the sin but also to his children, grandchildren and everyone on down to seven generations. The same is true to the most virtuous of the virtuous.

The great virtue of Venerable Maudgalyāyana having faith in the Lotus Sūtra not only made himself a Buddha but also his parents Buddhas. Moreover, all the parents in seven generations above and below, and all the parents in the limitless generations above and below became Buddhas unexpectedly. In addition, sons, husbands and wives, their retainers, devotees, and an incalculable number of people all were emancipated from the three evil realms. Not only that, they all entered the rank of shoji and eventually attained Buddhahood. Therefore, it is preached in the Lotus Sūtra, fascicle 3 (“Parable of a Magic City” chapter), “May this merit be spread over all living beings so that we and all others may attain Buddhahood together.”

Urabon Gosho, On theUllambana Service, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 175