大方廣佛華嚴經疏 1.10

1.10

二酬宿因者，何以法爾如是轉耶？宿因深故。夫根深則果茂、源遠則流長，宿因既深，教起亦大。深大云何？我佛世尊創躡玄蹤、棲神妙寂，悲智雙運、行願齊周，是以妄想弗翦而廓徹性空、靈鑑匪磨而頓朗萬法，乃以無障礙解脫闡斯沙門宿因雖多略有二種：一者大願力故。〈現相品〉云「毘盧遮那佛，願力周法界，一切國土中，恒轉無上輪。」〈兜率偈〉云「如來不出世，亦無有涅槃。以本大願力，示現自在法。」諸會佛加，皆言願力，及餘諸文成證非一。二者昔行力故。謂無量劫依願起行，行成得果方能頓演。故主山神偈云「往修勝行無有邊，今獲神通亦無量。法門廣闢如塵數，悉使眾生深悟喜。」

Second, to repay past causes: Why is it naturally turned in this manner? Because past causes are deep. When roots are deep, the fruit flourishes; when the source is far, the stream flows long. Since past causes are deep, the arising of the teaching is also great. What are 'deep' and 'great'? When our Buddha Bhagavat first stepped upon the profound traces and settled his spirit in wondrous silence, compassion and wisdom operated together, and practice and vows were equally fulfilled. Consequently, without cutting off delusive thoughts, he thoroughly penetrated the emptiness of nature; without polishing the spiritual mirror, he suddenly illuminated the myriad phenomena. Thus, through unobstructed liberation, he expounded this sūtra. / Although past causes are many, in brief there are two kinds: First, by the power of great vows. The 'Appearance of Marks Chapter' states: 'Vairocana Buddha's vow-power pervades the dharmadhātu; in all lands he constantly turns the unsurpassed wheel.' A verse in the Tuṣita Heaven states: 'The Tathāgata does not appear in the world, nor does he enter nirvāṇa; by the power of his original great vows, he displays sovereign Dharmas.' The empowerment of the Buddha at each assembly is always attributed to vow-power, and there is more than one textual proof of this. Second, by the power of past practice. This means that for immeasurable kalpas, relying on vows he initiated practices; when practice was perfected and the fruit attained, only then could he suddenly expound it. Hence the verse of the Mountain-Ruling Spirit states: 'His past cultivation of superior practice had no bounds; his attainment of supernormal powers today is likewise immeasurable. He opens wide the Dharma-doors as numerous as dust motes, causing all sentient beings to awaken deeply and rejoice.'