Madhvaon Brahma Sūtra 3.3.50

The direct perception of Brahman is produced not merely by study of scripture, etc., by the grace of the preceptor, but also by means of devotion, etc., (added to them). “Whatever the preceptor who is possessed of all auspicious marks, full of wisdom and devotion to the Lord (Vishnu), graciously imparts to the pupil, does not fail to bear its intended fruit. However, it is only by virtue of devotion and other qualities, which the individual soul eternally possesses as part of his essential nature, he obtains the grace of the preceptor; hence, only from his devotion, etc., that perception arises.” Further it is said in the Narayana Tantra: “ The devotion to the Lord Vishnu and the preceptor secures him the grace of the preceptor, as the virtues of tranquillity, etc., do; and thereby these virtues become further developed ; and by all the virtues so developed as well as by hearing, etc., the sight of Vishnu is obtained.”