法苑珠林 4.50

4.50

復何因緣是月宮殿圓淨滿足。亦三因緣故令如是。一爾時月天宮殿面相轉出。二青色諸天一切皆青。當半月中隱。於十五日時形最圓滿光明熾盛。譬如於多油中然火熾炬。諸小燈明皆悉隱翳。如是月宮十五日時能覆諸光。三復次日。宮殿六十光明。一時流出障月輪者。此月宮殿十五日時圓滿具足。於一切處皆離翳障。是時日光不能隱覆。復何因緣。月天宮殿。於黑月分第十五日一切不現。此月宮殿於黑月分十五日最近日宮。由彼日光所覆翳故一切不現。復何因緣名為月耶。此月宮殿於黑月分。一日已去乃至月盡。光明威德漸漸減少。以此因緣名之為月（西方一月分為黑白。初月一日至十五日。名為白月。十六日已去至於月盡。名為黑月。此方通攝黑月合為一月也）復何因緣月宮殿中有諸影現。此大洲中有閻浮樹。因此樹故。名閻浮洲其樹高大影現月輪。又瑜伽論云。由大海中有魚鼈等。影現月輪。故於其內有黑相現（依西國傳云。過去有兔。行菩薩行。天帝試之索肉欲食。捨身火中。天帝愍之取其燋兔置於月內。令未來一切眾生舉目瞻之。知是過去菩薩行慈之身）。

"Again, by what causes and conditions is this lunar palace round, pure, and complete?" "There are also three causes and conditions that make it so: first, at that time the face of the Moon Deva's palace turns toward [us]; second, the blue-colored devas, who are all blue, conceal it during half the month, but on the fifteenth day [the moon's] form is most complete and its light is blazing, just as when a blazing torch is lit in abundant oil, all smaller lamp lights are hidden and obscured—in this way, the lunar palace on the fifteenth day can overshadow all other lights; third, further, regarding the sixty rays of light from the sun's palace that flow forth at one time to obstruct the lunar orb, on the fifteenth day this lunar palace is round and fully complete, free from obstruction everywhere, and at this time the sun's light cannot conceal it. Furthermore, by what cause and condition does the palace of the Moon Deva not appear at all on the fifteenth day of the dark fortnight? This lunar palace on the fifteenth day of the dark fortnight is closest to the sun's palace, and because it is covered and obscured by the sun's light, it does not appear at all. Furthermore, by what cause and condition is it called 'moon' (yue)? From the first day of the dark fortnight until the end of the month, the radiance and majesty of this lunar palace gradually diminish (que), and for this reason it is called the moon (yue). (In the Western regions, a single month is divided into dark and bright: from the first day of the waxing moon to the fifteenth day is called the bright fortnight; from the sixteenth day to the end of the month is called the dark fortnight. Here [in China], the dark fortnight is included together with it to make one month.) Furthermore, by what cause and condition do various shadows appear within the lunar palace? In this great continent there is a jambu tree; because of this tree, it is called Jambudvīpa. That tree is tall and large, and its shadow appears upon the lunar orb. Furthermore, the Yogācārabhūmi-śāstra states that because there are fish, turtles, and the like in the great ocean, their shadows appear upon the lunar orb, and therefore dark forms appear within it. (According to the Records of the Western Regions, in the past there was a hare practicing the bodhisattva path. The Lord of Devas tested it by demanding meat to eat, and it threw itself into a fire. The Lord of Devas took pity on it, took the scorched hare, and placed it inside the moon, so that all future sentient beings, looking up at it, would know that this was the past body of a bodhisattva practicing compassion.)"