Any person who is chanting the holy names of Krishna (Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare) in course of chanting without offenses feels some transcendental pleasure and very quickly becomes puriﬁed of all material contamination.
Bhagavat Gita 9.2,
Caitanya Mahaprabhu has recommended that everyone chant the Hare Krishna mantra just to cleanse the dust from the heart. If the dust of the heart is cleansed away, then one can actually understand the importance of the holy name.
Nectar of Devotion, Chapter 12,
The sound vibration of the Hare Krishna mantra, although presented in the ordinary alphabet, should not be taken as mundane or material.
Srimad bhagavatam 4.9.4,
The best means of spiritual realization is chanting the holy name of the Lord.
Bhagavad Gita 6.11-12,
Krishna is present fully in His holy name and this is realized by the humility and sincerity in our chanting.
In this material world there are only two representatives of the Supreme Personality of Godhead; the transcendental sound vibration of the Holy Name and his eternally transcendental deity incarnation.