大毘盧遮那成佛經疏 1.3

1.3

「大毘盧遮那成佛神變加持」者，梵音毘盧遮那者是日之別名，即除暗遍明之義也。然世間日則有方分，若照其外不能及內，明在一邊不至一邊，又唯在晝光不燭夜；如來智慧日光則不如是，遍一切處作大照明矣，無有內外方所晝夜之別。復次日行閻浮提，一切卉木叢林隨其性分各得增長，世間眾務因之得成；如來日光遍照法界，亦能平等開發無量眾生種種善根，乃至世間、出世間殊勝事業莫不由之而得成辦。又如重陰昏蔽日輪隱沒亦非壞滅、猛風吹雲日光顯照亦非始生，佛心之日亦復如是，雖為無明煩惱戲論重雲之所覆障而無所減、究竟諸法實相三昧圓明無際而無所增。以如是等種種因緣，世間之日不可為喻，但取其少分相似，故加以大名，曰摩訶毘盧遮那也。

As for "Mahāvairocana-abhisaṃbodhi-vikurvitādhiṣṭhāna": the Sanskrit word Vairocana is an alternative name for the sun, meaning to dispel darkness and illumine everywhere. However, the mundane sun has spatial bounds: if it illumines the outside, it cannot reach the inside; when light is on one side, it does not reach the other side; and moreover it shines only by day, its light not illuminating the night. The tathāgata's sunlight of wisdom is not like this: it provides great illumination everywhere, without distinction of inside or outside, direction or location, day or night. Furthermore, when the sun moves across Jambudvīpa, all grasses, trees, thickets, and forests grow in accordance with their respective natures and shares, and all mundane tasks are thereby accomplished; the tathāgata's sunlight shines everywhere upon the dharmadhātu, and can also equally unfold the various good roots of immeasurable sentient beings, so that even mundane and supramundane excellent activities are all brought to completion by means of it. Furthermore, just as when heavy overcast darkens and conceals the solar disc, its disappearance is not destruction, and when a fierce wind blows away the clouds and the sunlight shines brilliantly, it is not a new birth, the sun of the Buddha-mind is also like this: although covered and obstructed by the heavy clouds of avidyā, afflictions, and prapañca, it does not decrease; and when the samādhi of the dharmatā of all dharmas is fully realized, perfectly clear and boundless, it does not increase. Through such various conditions, the mundane sun cannot serve as a [complete] metaphor; taking only a partial resemblance, the great name is added, calling him Mahāvairocana.