Srimad Bhagavad-Gita :
Slokam-5. ( That knowledge of the field of activities and of the knower of activities is described by various sages in various Vedic writings-especially in the Vedānta-sūtra-and is presented with all reasoning as to cause and effect. )
rshibhirbahudha gitam chandobhir vividhaih prthak,
brahmasutrapadaiscaiva hetumadbhir viniscitaih.
rshibhih bahudha = by Rishi-s in many ways;
vividhaih chandobhih = many different Vedic mantra-s ( hymens );
hetumadbhih viniscitaih = with cause and effect and ascertain ( certain and sure );
brahma-sutrapadais eva ca = the vedantam and aphorism too;
( etat) prthak gitam = variously described ( this specially reflected ).
Categorically as well the distinct characteristics by which the ksetra and ksetrajna exist and their manifestation by the brahman or spiritual substratum pervading all existence is revealed…