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,
The ultimate goal of Bhakti is to get Krishna and we get it by taking shelter of the holy name.
To chant the holy name and dance in ecstasy is so easy and sublime that one can achieve all the benefits of spiritual life simply by following this process.
Srimad Bhagavatam 6.2.11,
The Hare Krishna mahamantra is also a prayer, for a prayer addresses the Supreme Personality of Godhead by His name and invokes good fortune by petitioning the Lord to allow one to engage in His devotional service.
Srimad Bhagavatam 4.24.69,
Of sacriﬁces I am the chanting of the holy names [japa].
Bhagavat Gita 10.25
Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare. In Kali-yuga, if this Vedic maha-mantra is chanted regularly and heard regularly by the devotional process of shravanam kirtanam, it will purify all societies, and thus humanity will be happy both materially and spiritually.
Srimad Bhagavatam 4.18.14,