三彌勒經疏 1.211

1.211

經曰「其城中有大波羅門」以下，第二辨人勝。此中二：初託父母受身、後厭世出家成佛。是初也。妙梵者，父名也。婆羅門者，姓名也。釋迦生王種中。彌勒生輔臣姓中，化眾生宜不同也。梵摩婆提者，此言淨道也。梵摩婆提者，還西國婆羅門姓。身長千尺者，千尺者計即百丈。爾時人身長半卑，謂五千十。古言掌與身十分一，若胸與身五分一。謂若人身長八尺，面及掌並八寸，胸廣一尺六寸。是故釋迦身長丈六，計十六尺，面掌並一尺六寸，胸廣三尺二寸，爾乃相稱。既彌勒身百丈，面應十丈，而今此云二丈四尺者，恐傳經者誤也。

From the sūtra passage stating, "In that city there is a great brāhmaṇa," onward is the second [section], which explains the superiority of the person. Within this there are two parts: first, taking a body dependent on parents; and second, wearying of the world, leaving home, and attaining Buddhahood. This is the first. "Subrahma" is the father's name. "Brāhmaṇa" is the clan name. Śākyamuni was born into the royal lineage, whereas Maitreya is born into the clan of a minister; what is suitable for transforming sentient beings is not the same. "Brahmavatī" means "pure way" here. Brahmavatī is likewise a brāhmaṇa clan of the Western Regions. "The body being one thousand feet in height": one thousand feet calculates to one hundred zhang. At that time, a person's body was half a bēi in height, which means five thousand and ten. Ancient texts say that the palm is one-tenth of the body, and the chest is one-fifth of the body. That is, if a person's body is eight feet tall, the face and palms are both eight inches, and the chest is one foot six inches wide. Therefore, Śākyamuni's body was sixteen feet tall—calculating to sixteen feet—his face and palms were both one foot six inches, and his chest was three feet two inches wide; only then are they proportionate. Since Maitreya's body is one hundred zhang, his face ought to be ten zhang; yet this text now says "two zhang four feet," which is probably an error by the transmitters of the scripture.