瑜伽論記 9.417

9.417

言若無堪能，為說正法，伴助令彼發生正行者，謂彼所化若無堪能起於正行，菩薩伴助與共同行，復為說法令發起行，親教師是闍梨，軌範師是和上。

Regarding the statement, 'If they lack capability, preaching the true Dharma to them, and assisting them as a companion to cause them to give rise to correct practice': this means that if the one to be transformed lacks the capability to initiate correct practice, the bodhisattva assists them as a companion, practicing together with them, and further preaches the Dharma to them to make them initiate practice. The personal preceptor is the ācārya, and the disciplinarian is the upādhyāya.