大般涅槃經義記 3.119

3.119

就初句中，諸佛淨行名婆羅門，依從化生名婆羅門子，依化不並是故言一。法身充美名「在弱冠」，持戒無犯名「修淨行」，大悲垂接名「長髮相」，博通聖教名「善呪術」。

In the first clause, the pure conduct of the buddhas is called 'brāhmaṇa'; relying on and being born from the transformation is called 'the son of a brāhmaṇa'; because the reliances do not appear together in their transformations, it says 'one.' The dharmakāya being abundant and beautiful is called 'at the age of capped youth.' Maintaining the precepts without infraction is called 'cultivating pure conduct.' Great compassion extending down to receive beings is called 'the mark of long hair.' Being broadly versed in the holy teachings is called 'skilled in spells and arts.'