佛說觀佛三昧海經 8.27

8.27

佛告阿難：「佛滅度後，天眾、龍眾、夜叉眾、沙門眾、婆羅門眾，問佛世尊過去世時清淨無欲修諸梵行得何果報？汝當答言：『佛有馬王藏相，與身平等七合盈滿，如金剛器中外俱淨，為度眾生出現是相，化佛光明妙蓮華雲其數無量，如此身者，從無數世無染安隱善持戒、慧、尸，波羅蜜生。』」

The Buddha told Ānanda: “After the Buddha's parinirvāṇa, when the hosts of devas, nāgas, yakṣas, śramaṇas, and brāhmaṇas ask: ‘What retribution did the Buddha, the Bhagavat, attain by cultivating pure conduct in past lives, being pure and devoid of desire?’ you should answer them: ‘The Buddha possesses the horse-king sheath mark, which is proportionate with his body, perfectly filled in its seven convexities, pure inside and out like a vajra vessel. For the sake of saving sentient beings, he manifests this mark, along with immeasurable transformation Buddhas, light, and wondrous lotus clouds. Such a body arises from countless lives of being unstained and at peace, properly upholding moral discipline, wisdom, and the śīla-pāramitā.’”