"The Lord can be realized through the aural reception of the transcendental message, and that is the only way to experience the transcendental subject. As fire is kindled from wood by another fire, the divine consciousness of man can similarly be kindled by another divine grace. His Divine Grace the spiritual master can kindle the spiritual fire from the woodlike living entity by imparting proper spiritual messages injected through the receptive ear. Therefore one is required to approach the proper spiritual master with receptive ears only, and thus divine existence is gradually realized."

Srimad-Bhagavatam 1:2:32