The essence of each religion is to transform our consciousness to reestablish our relationship with Lord.
Religion is the science of the soul, the science of consciousness, the science which reveals to us who we are, what is our nature, who is God and our relationship with Him.
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