Madhvaon Brahma Sūtra 3.4.12

“ He who is not devoted to Vishnu, who is destitute of dutifulness to his preceptor, who is devoid of tranquil- lity and other virtues, as well as one who is not of the three twice-born classes, is not eligible for the study of the Vedas or for the performance of Vedic duties; there- fore, he who is possessed of Vedic learning together with the virtues mentioned above is certainly considered by the wise to be fit for the knowledge of Brahman to be derived by means of the Vedas ” (Brahma Tarka). The Kausharava Sruti speaks to the same effect: “ He shall read the Vedas; he shall study their meaning; then having made enquiries, he shall reach Brahman.”