釋氏要覽 3.314

3.314

不空骨索經云。諸佛神通之月○智論云。天帝釋以大寶鏡。從正月照南剡部洲二月照西洲。至五九月。皆照南洲。察人善惡故。南洲人多於此月。素食修善。故經云。年三長齋也。又一說。北方毘沙門天王。巡察四洲善惡。正月至南洲。亦如鏡照至五九月。皆察南洲故。

The Amoghapāśa-sūtra says: "These are the months of the Buddhas' supernatural powers." The Mahāprajñāpāramitopadeśa says: "Śakra, Lord of the Devas, uses a great jewel mirror to illuminate the southern continent of Jambudvīpa in the first month, the western continent in the second month, and in both the fifth and ninth months illuminates the southern continent, in order to inspect people's good and evil deeds. Therefore, the people of the southern continent mostly eat vegetarian food and cultivate good during these months." Hence the sūtra speaks of "the three long fasts of the year." Another explanation says: "Vaiśravaṇa, the Heavenly King of the North, patrols and inspects the good and evil of the four continents. In the first month he reaches the southern continent, and just as with the mirror's illumination, in both the fifth and ninth months he inspects the southern continent; hence [the practice]."