"So Lord Krishna, Lord Caitanya, He introduced this Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare for this age. And He recommended, kalau... Not recommended by His own brain, but it is recommended in the scriptures:
harer nama harer nama harer nama eva kevalam
kalau nasty eva nasty eva nasty eva gatir anyatha
(Cc. Adi 17.21)
If you want to realize the Supreme Truth, then you must realize this: Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare, whenever you get... Harer nama harer nama harer nama eva kevalam: 'Only this.' And if you think, 'Oh, only this? Why not other?' No. Kalau nasty eva nasty eva nasty eva gatir anyatha. Nasty eva means 'There is no alternative.' And He repeats this: 'no alternative, no alternative, no alternative,' three times. Three times. That means He is giving too much stress. So our process is like that, that we are following a great personality, Lord Sri Caitanya Mahaprabhu. He introduced from the scripture, not in His own way. Nothing should be accepted which is not recognized. You see? So this is recognized method. Now it depends on us. Let us follow this process and see how we are making progress in the spiritual path. You see?"
(Srila Prabhupada lecture, New York, September 8, 1966)