SB 12.8.48
yam vai na veda vitathaksa-pathair bhramad-dhih
santam svakesv asusu hrdy api drk-pathesu
tan-mayayavrta-matih sa u eva saksad
adyas tavakhila-guror upasadya vedam
Translation:
A materialist, his intelligence perverted by the action of his deceptive senses, cannot recognize You at all, although You are always present within his own senses and heart and also among the objects of his perception. Yet even though one’s understanding has been covered by Your illusory potency, if one obtains Vedic knowledge from You, the supreme spiritual master of all, he can directly understand You.