We Should know in perfect consciousness that human life is bestowed upon the conditioned soul to achieve spiritual success and the easiest possible procedure to attain this end is to chant the holy name of the Lord. – Srimad Bhagavatam, 02.01.12.
By chanting Krishna’s names, one will be transferred to the supreme planet, Krishnaloka, without a doubt.
Bhagavad-gita 8.7,
Srila Prabhupada
In this age no process of realizing the Supreme is possible except the chanting of the holy names of Lord Krishna: Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare.
Bhagavad-gita 8.11,
Srila Prabhupada
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,
Srila Prabhupada
The chanting itself purifies us and as the heart becomes purified, the Holy name is revealed to us as being non-different than Lord Krishna.
One can attain salvation simply by chanting the holy name of the Lord.
Srimad Bhagavatam 1.18.7