'dvitīya catur-vyūha' ei--turīya, viśuddha
vāsudeva-the expansion named Vāsudeva; saṅkarṣaṇa-the expansion named Saṅkarṣaṇa; pradyumna-the expansion named Pradyumna; aniruddha-the expansion named Aniruddha; dvitīya catuḥ-vyūha-the second quadruple expansion; ei-this; turīya-transcendental; viśuddha-free from all material contamination.
Vāsudeva, Saṅkarṣaṇa, Pradyumna and Aniruddha constitute this second quadruple. They are purely transcendental.
(2) In answer to Śaṅkarācārya's commentary on Vedānta-sūtra 2.2.43, it must be said that the original Viṣṇu of all the Viṣṇu categories, which are distributed in several ways, is Mūla-saṅkarṣaṇa. Mūla means "the original." Saṅkarṣaṇa is also Viṣṇu, but from Him all other Viṣṇus expand. This is confirmed in the Brahma-saṁhitā, wherein it is said that just as a flame transferred from another flame acts like the original, so the Viṣṇus who emanate from Mūlasaṅkarṣaṇa are as good as the original Viṣṇu. One should worship that Supreme Personality of Godhead, Govinda, who thus expands Himself.