大方廣佛華嚴經隨疏演義鈔 84.51

84.51

疏「迦旃延」者，即大乘法師釋，謂上古多仙，山中靜處年歲既久，鬢髮稍長無人為剃，婆羅門法要剃髮故。一仙有子，兄弟二人俱來觀父，小者乃為諸仙剃之。諸仙願護，後成仙道，爾來此種皆稱剪剃。

Regarding the Commentary's mention of 'Kātyāyana': this is explained by the Mahāyāna master, who says that in antiquity there were many seers who lived in secluded mountain retreats for long years; their hair and temples grew long and there was no one to shave them, yet the Brahmanical rule required shaving the hair. One seer had sons; two brothers came together to visit their father, and the younger one shaved all the seers. The seers vowed to protect him, and later he attained the path of a seer; ever since, this lineage has been called 'Shaving'.