By His Divine Grace A. C. Bhaktivedanta Swami Prabhupada
The scriptures advise us to chant only the name of the Supreme Personality of Godhead, Krishna. There are thousands of names of Vishnu, and in once sense Krishna and Vishnu are the same, yet the scriptures explain that chanting a thousand names of Vishnu gives the result of chanting the name Rāma just once, and chanting Rāma three times gives the result of chanting Krishna once. In other words, one automatically gets all good results just by chanting the holy name of Krishna.
Caitanya Mahāprabhu therefore recommends this chanting process, according to Śāstric injunction:
harer nāma harer nāma harer nāmaiva kevalam
kalau nāsty eva nāsty eva nāsty eva gatir anyathā [Cc. Ādi 17.21]
“In this age of quarrel and hypocrisy, the only means of deliverance is chanting the holy name of the Lord. There is no other way. There is no other way. There is no other way.” (Brhan-nāradīya Purāna)
By taking up this chanting process, we are immediately freed from all sinful reactions. Thus we begin our spiritual life. Without being freed from sinful life, there is no possibility of becoming a pure Vaishnava.
[An excerpt from “A Second Chance – The Story of a Near-Death Experience”, available at your nearest Hare Krishna Center]