大毘盧遮那成佛經疏 3.17

3.17

經云「復次祕密主！如天降雨生泡，彼真言悉地種種變化，當知亦爾」者。聲聞經以受譬浮泡，《般若》中以泡為喻，雖實無性，而因緣猶是實法，欲十句中有如化而不明泡喻。今此經譬意復殊也。如夏時雨水，自雨水中隨渧之大少生種種浮泡，形類各異，然水性一味，自為因緣。四句推求，無別所生之法，是故此泡舉體從緣。泡起即是水起、泡滅即是水滅，故以此喻即心之變化也。如行者即以自心作佛，還蒙心佛示悟方便，轉入無量法門。又以心為漫荼羅，此境與心為緣，能作種種不思議變化。是故行者以浮泡喻觀之，了知不離自心，故不生著也。《釋論》又云「修定者有十四變化，天龍鬼神亦能作化，如化生光無定物，但以心生便有、心滅則滅，是法無初中後，生是無所從來、滅亦無所至，當知諸法亦如是。復次如變化相，清淨如虛空無所染著，不為罪福所污。諸法亦爾，法性、如如、實際自然常淨。譬如閻浮提四大河，一一河有五百小河以為眷屬，此水種種不淨，入大海中皆悉清淨。」與泡喻意同也。

The sūtra says: “Furthermore, Lord of Mysteries! Just as when heaven sends down rain, bubbles are born, the various transformations of mantra-siddhi should be known to be also like this.” The Śrāvaka sūtras compare sensation to a floating bubble, while in the Prajñā[pāramitā sūtras] bubbles are used as a simile: although they have no real intrinsic nature, the causes and conditions are still real phenomena; among the ten similes, there is 'like an illusion/transformation', but the bubble simile is not clarified. Now the meaning of this sūtra's simile is again distinct: like rainwater in the summer, from within the rainwater various floating bubbles are born according to whether the drops are large or small, their shapes and types being diverse, yet the nature of water has one flavor and serves as its own cause and condition. Inquiring through the four propositions, there is no distinct phenomenon produced; therefore this bubble entirely accords with conditions. The arising of the bubble is the arising of water; the ceasing of the bubble is the ceasing of water; therefore this simile is used for the transformations of the mind itself. For instance, the practitioner, taking their own mind itself as the Buddha, is in turn shown the upāya of awakening by the mind-Buddha, entering progressively into immeasurable Dharma gateways. Furthermore, taking the mind as the maṇḍala, this object serves as a condition for the mind, able to produce manifold inconceivable transformations. Therefore, the practitioner contemplates with the simile of a floating bubble, knowing it is not separate from their own mind, and thus does not give rise to attachment. The Expository Treatise also says: “Those who cultivate concentration possess fourteen transformations; devas, nāgas, ghosts, and spirits can also perform transformations. Like magically created light having no fixed substance, it exists simply when the mind gives rise to it, and ceases when the mind ceases; this phenomenon has no beginning, middle, or end; its arising comes from nowhere, and its cessation goes nowhere; one should know that all phenomena are also like this. Furthermore, just as the mark of transformation is pure like empty space without defilement and not stained by sin or merit, all phenomena are also like this: the nature of phenomena, suchness, and the reality-limit are spontaneously and ever pure. For example, the four great rivers of Jambudvīpa each have five hundred minor rivers as their retinue; these waters have manifold impurities, but entering the great ocean, they all become pure.” This shares the same meaning as the bubble simile.