Prabhupada's lecture - Śrīmad-Bhāgavatam 1.7.19 - Vṛndāvana, September 16, 1976

So mantra is powerful. This is mundane. Now you can imagine how spiritual mantra is powerful. Even in mundane world the mantra acts. This is very subtle thing. Then how much... Because

indriyāṇi parāṇy āhur
indriyebhyaḥ paraṁ manaḥ
manasas tu parā buddhir
yo buddheḥ paratas tu saḥ
[Bg. 3.42]

So gross understanding—the senses, the body, directly sense perception—this is gross. I see you, you see me. I touch you, you touch me. I taste something... This is gross. Above this gross there is mental platform. So mantra is also on the mental, little above, intelligence. And above that there is spiritual platform. So if on the material platform, mental platform, the mantra can act so wonderfully, how much spiritually the mantra can benefit you. You have to simply imagine. So this Hare Kṛṣṇa mantra is completely spiritual. If you chant it, spiritually enlightened, then surely it will act. Paraṁ vijayate śrī-kṛṣṇa-saṅkīrtanam. It will act. Therefore chanting is so important.
Chanting is not... Narottama dāsa Ṭhākura said this sound vibration is not this material sound. Kṛṣṇa is not material sound. It is Kṛṣṇa, spiritual. Abhinnatvān nāma-nāminoḥ. There is no difference between Kṛṣṇa, the Supreme Personality of Godhead, and His holy name, Kṛṣṇa. There is no difference.

nāma cintāmaṇiḥ kṛṣṇaś
pūrṇaḥ śuddho nitya-mukto
'bhinnatvān nāma-nāminoḥ
[Cc. Madhya 17.133]

As Kṛṣṇa is pūrṇa, perfect, complete, śuddha, without any material contamination. Pūrṇaḥ śuddho nitya, eternal. Pūrṇaḥ śuddho nitya-muktaḥ. Mukta means not of this material world. Mukti means anything which does not belong to, in this material world. That is called mukti. So the holy name, chanting of holy name, if we act it properly, without any offense, then we are directly in connection with Kṛṣṇa. There is no doubt. Pūrṇaḥ śuddho nitya-mukto 'bhinnatvān nāma-nāminoḥ.

Hare Krishna Hare Krishna Krishna Krishna Hare Hare

Hare Rama Hare Rama Rama Rama Hare Hare