It is a Buddhist ceremony in which we transfer merits to our ancestors to alleviate their sufferings. These merits are gained from our sincere reverence to the Buddha and offerings to the Sangha. Hence we are actually making offerings to the Triple Gems and expressing filial piety to our parents and repaying their kindness.
The ceremony is conducted in accordance with the essential meaning as expounded in the Ullambana Sutra. According to the sutra, Maudgalyayana had attained enlightenment and with his divine eyes, he could see his late mother suffering in the hungry ghost realm. He tried to save her with his supernatural powers but to no avail. Hence, he sought advice from the Buddha to save his mother. Buddha told him that the Sangha had practised diligently during the three months’ summer retreat and accrued boundless merits. On the 15th day of the 7th lunar month, while the Sangha members observed confession, Buddhists who were able to pay respects to the Buddha and make offerings to the Sangha on behalf of their ancestors and parents, could transfer the merits gained to them. This act would help to alleviate the sufferings of the deceased in the hungry ghost realm and bless the living with good fortune, happiness and well-being.
法会根据《佛说盂兰盆经》的意义而举行，经说：目连悟道以后，以天眼见其亡母堕于鬼道受苦，他使尽神力不能救拔，请佛开示救济的办法。佛说：众僧在夏季 “结夏安居” 三个月，精进修行，功德无量，在农历七月十五日举行僧自恣日。佛弟子可以在当天为存亡的祖先或父母敬佛供僧，借此功德回向，使亡者脱离鬼道的苦难或生者得到福乐平安。