佛說盂蘭盆經疏 2.85

2.85

"Good sons! If monks, nuns, kings, crown princes, grand ministers, prime ministers, the three dukes, the hundred officials, and the myriad common people who practice loving-kindness and filial piety would do so, they should all first, for the sake of the parents who gave birth to them in the present life and their past parents of seven lifetimes, on the fifteenth day of the seventh month—the day of the Buddha's joy, the day of the saṅgha's pravāraṇā—place foods and drinks of a hundred delicacies within an Ullambana basin and offer them to the pravāraṇā saṅgha of the ten directions."