The beginning of Kṛṣṇa consciousness and devotional service is hearing, in Sanskrit called sravanam. All people should be given the chance to come and join devotional parties so that they may hear. This hearing is very important for progressing in Kṛṣṇa consciousness. When one links his ears to give aural reception to the transcendental vibrations he can quickly become purified and cleansed in the heart. Lord Caitanya has affirmed that this hearing is very important. It cleanses the heart of the contaminated soul so that he becomes quickly qualified to enter into devotional service and to understand Kṛṣṇa consciousness.
In the Garuda Purana the stress on hearing is expressed very nicely. It is said there: “The state of conditioned life in the material world is just like a man lying unconscious, having been bitten by a snake. This is because both such unconscious states can be ended by the sound of a mantra.” When a man is snake-bitten he does not die immediately, but first becomes unconscious and remains in a comatose condition. Anyone who is in the material world is also sleeping, as he is ignorant of his actual self or his actual duty and his relationship with God. So materialistic life means that one is bitten by the snake of maya, illusion, and thus, without any Kṛṣṇa consciousness, he is almost dead. Now the so-called dead man bitten by a snake can be brought back again to life by the chanting of some mantra. There are expert chanters of these mantras who can perform this feat. Similarly, one can be brought back into Kṛṣṇa consciousness from the deadly unconscious state of material life by hearing of the maha-mantra: Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare.
In the Fourth Canto of Srimad-Bhagavatam, Twenty-ninth Chapter, verse 40, the importance of hearing of the pastimes of the Lord is stated by Sukadeva Gosvami to Maharaj Pariksit: “My dear King, one should stay at a place where the great acaryas [holy teachers] speak about the transcendental activities of the Lord, and one should give aural reception to the nectarean river flowing from the moonlike faces of such great personalities. If someone eagerly continues to hear such transcendental sounds, then certainly he will become freed from all material hunger, thirst, fear and lamentation, as well as all illusions of material existence.”
Sri Caitanya Mahaprabhu also recommended this process of hearing as a means of self realization in the present age of Kali. In this age it is very difficult to follow thoroughly the regulative principles and studies of the Vedas which were formerly recommended. However, if one gives aural reception to the sound vibrated by great devotees and acaryas, that alone will give him relief from all material contamination. Therefore it is the recommendation of Caitanya Mahaprabhu that one should simply hear from authorities who are actually devotees of the Lord. Hearing from professional men will not help. If we hear from those who are actually self realized, then the nectarean rivers, like those which are flowing on the moon planet, will flow into our ears. This is the metaphor used in the above verse.
As is stated in Bhagavad-gita, “A materialistic person can give up his material hankerings only by becoming situated in Kṛṣṇa consciousness.” Unless one finds a superior engagement he will not be able to give up his inferior engagement. In the material world everyone is engaged in the illusory activities of inferior energy, but when one is given the opportunity to relish the activities of the superior energy performed by Kṛṣṇa, then he forgets all his lesser pleasures. When Kṛṣṇa speaks on the battlefield of Kuruksetra, to the materialistic person it appears that this is simply talk between two friends, but actually it is a river of nectar flowing down from the mouth of Sri Kṛṣṇa. Arjuna gave aural reception to such vibrations, and thus he became freed from all the illusions of material problems.
Source: A.C. Bhaktivedanta Swami Prabhupada (2011 edition), “The Nector of Devotion”, Page 89 & 90