Madhvaon Brahma Sūtra 3.2.23

That, Brahman, is by nature always non-manifest; .(hence in obtaining the direct vision of the Lord, the soul’s efforts are of no avail without His grace). Ac- cordingly the Kauntharavya Sruti says, “ Brahman is the Imperishable, is never manifest; it is without (physi- cal) form or colour, without parts; having seen whom the soul obtains release, yea, undiminishable and eternal bliss.’’