成唯識論演祕 6.271

6.271

所言成者，具如疏引。所言得者，《顯揚》十八云：「問：以誰為先？誰為建立？誰和合？故得何法耶？答：三乘種姓為先；內因力為建立；外因力為和合故；證得煩惱離繫涅槃。」此中內因力者，謂如理作意、小欲知足等內分善法，又得人身生在聖處諸根無缺無諸業障，於如來所具淨信心，如是等法是名「內因力」。外因力者，謂諸佛出世宣說妙法，住正法者共為伴侶，具悲信者以為施主，如是等法名「外因力」。

As for what is called 'completing', it is fully explained as cited in the Commentary. As for what is called 'obtaining', the Prakaraṇāryavācā, fascicle 18, states: 'Question: Taking what as precursor? Established by what? Through the harmony of what? What phenomena are obtained? Answer: Taking the lineage (gotra) of the three vehicles as precursor; established by internal causal power; through the harmony of external causal power; one realizes and obtains nirvāṇa, which is dissociation from afflictions.' Here, 'internal causal power' refers to wholesome states belonging to the internal sphere such as appropriate attention (yoniśo-manaskāra) and having few desires and being content, as well as obtaining a human body, being born in a noble place, having unimpaired faculties, being free from karmic obstacles, and possessing pure faith in the Tathāgata—such phenomena are called 'internal causal power'. 'External causal power' refers to Buddhas appearing in the world to proclaim the sublime Dharma, having companions who abide in the correct Dharma, and having donors endowed with compassion and faith—such phenomena are called 'external causal power'.