"So don't spoil the movement by manufacturing ideas. Don't do that. Go on in the standard way, keep yourself pure; then movement is sure to be successful. But if you want to spoil it by whimsical, then what can be done? It will be spoiled. If you manufacture whims and disagree and fight amongst yourself, then it will be another edition of these so-called movements. It will lose the spiritual strength. Always remember it. You cannot.... Now, actually, people are surprised: "What this Hare Kṛṣṇa mantra has got power that it is changing so quickly?" And on the other hand, it is to be admitted, unless it has got power, how it is changing? So we have to keep that power. Don't make it an ordinary musical vibration. It is a different thing, spiritual. Although it seems like musical vibration, but it is spiritual, completely. Mantrauśadhi-vaśa. Even, by mantra, the snakes can be charmed. So mantra is not ordinary sound vibration. So we have to keep the mantra in potency, potent, by offenseless chanting, by remaining pure. If you pollute the mantra, then it will lose its effect."
Srila Prabhupada's Room Conversation -- April 27, 1976, Auckland, New Zealand