The essence of each religion is to transform our consciousness to reestablish our relationship with Lord.
Simply by chanting the holy name of Krishna – Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare – a devotee of the Lord can approach the supreme destination easily and happily, but this destination cannot be approached by any other process of religion.
Purport on Bhagavad Gita 12.6
There are different religions because there are different levels of understanding God.
Lecture on "Memories of my youth" – 27th OCT'06 – DXB
The basic principle of every original religion in this world is discipline.
Srimad Bhagavatam it is repeatedly and clearly said that the essence of religion in the Age of Kali is the chanting of the holy name of Krishna.
Caitanya Caritamrta Adi lila 3.50
In this age of Kali there is no other religion but the glorification of the Lord by utterance of His holy name, and that is the injunction of all the revealed scriptures.