The holy name of Krishna is so attractive that anyone who chants it — including all living entities, moving and nonmoving, and even Lord Krishna Himself — becomes imbued with love of Krishna. This is the effect of chanting the Hare Krishna maha-mantra.
Chaitanya Caritamrta, Antya Lila 3.268,
This process of chanting is the best process of self-realization in this age; therefore Lord Caitanya preached it so nicely for the benefit of all humanity.
Srimad Bhagavatam 3.24.35,
Krishna is present fully in His holy name and this is realized by the humility and sincerity in our chanting.
Let people chant the Hare Krsna mantra constantly. Then their demoniac tendencies will be killed, and they will become first-class devotees, happy in this life and in the next.
Srimad Bhagavatam 6.2.14,
Chaitanya Mahaprabhu has recommended that everyone should 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.
When we hear about the Lord, we should hear with a spirit to serve the Lord. When we chant his names, we should chant so that He is pleased to hear us chanting. That is the beauty of life, the real art of living.