karmāśuklākṛṣṇaṃ yoginas trividham itareṣām [YS 4.7]
catuṣpadī khalv iyaṃ karmajātiḥ kṛṣṇā śuklakṛṣṇā śuklāśuklākṛṣṇā ceti. tatra kṛṣṇā durātmanām, śuklakṛṣṇā bahiḥsādhanasādhyā. tatra parapīḍānugrahadvāreṇaiva karmāśayapracayaḥ śuklā tapaḥsvādhyāyadhyānavatām. sā hi kevale manasy āyattatvād abahiḥsādhanādhīnā na parān pīḍayitvā bhavati. aśuklākṛṣṇā saṃnyāsināṃ kṣīṇakleśānāṃ caramadehānām iti tatrāśuklaṃ yogina eva phalasaṃnyāsād akṛṣṇaṃ cānupādānāt itareṣāṃ tu bhūtānāṃ pūrvam eva trividham iti.