佛說盂蘭盆經疏 2.45

2.45

The Tripiṭaka Master says: 'Even if you move the heavenly spirits of the upper realms and stir the earthly deities of the lower regions, even if you draw in demonic spirits and broadly gather non-Buddhists, unifying the six directions as a single family and combining the eight classes of beings as one assembly, uniting their spiritual powers would still be of no avail.' 'Non-Buddhist religious masters' means religious masters among the non-Buddhists, distinguished from religious masters within the Buddhist path. When Buddhism was first transmitted to this land, monks were called religious masters (daoshi). The 'Four Heavenly Kings' are Vaiśravaṇa and the others who protect and maintain the world.