Madhvaon Brahma Sūtra 1.3.37
Dvaita Vedānta
Sūtra
तदभावनिर्धारणे च प्रवृत्तेः
tadabhāvanirdhāraṇe ca pravṛtteḥ
Sūtra translation
And on account of (Haridrumata’s) proceeding (first) to ascertain (that Satyakama) Idas not (d Sudra), (with a view to initiating him).
“ O, sage, I do not know this, (namely) to what family I belong.” (Ch. IV. iv. 4). From this truthful statement by Satyakama, Haridrumata having (first) concluded that “ A non-brahmin is not capable of such truthful answer,” (ib), and consequently Satyakama was not a Sudra, pro- ceeded to perform the ceremony of initiation for him. Hence the Sudra is not eligible for the study of the Vedas