When my consciousness is to lord it over the material nature, that is material life, and when my consciousness is to serve Kṛṣṇa, the Supreme Lord, Kṛṣṇa consciousness, that is spiritual life. So as there are rules and regulation for accelerating your material possession, material life, similarly, there are rules and regulation for spiritual life also.
So the basic principle is yad icchantaṁ brahmacaryaṁ caranti. One should be very regular. Vīta-rāgāḥ. Viśanti yad, viśanti yad yatayo vīta-rāgāḥ. Vīta-rāgāḥ. Vīta-rāgāḥ means completely separated from materialistic life. Vīta-rāgāḥ. Rāgāḥ means attachment, and vīta means completely freed.
Yad akṣaram, yad akṣaraṁ brahma vido vadanti. Brahma-vida. Brahma . . . those who are conversant in Vedic literature. Akṣaram. Akṣaram. Yad akṣaram. The God has His representation in three letters, a, u, m, which is sounded vibrated oṁ. There is no difference between oṁkāra and Kṛṣṇa. It is admitted in the Bhagavad-gītā that oṁkāra 'smi. Akṣaram oṁkāro 'smi: "Of all the letters, I am the oṁkāra."
So Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare / Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare and oṁkāra, there is no difference, so far the transcendental sound vibration is concerned. But the objective is different. By oṁkāra one attains impersonal existence in the brahma-jyoti, and by chanting Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare, one attains the spiritual body, and he's situated in the spiritual planets.
We have many times discussed that there are spiritual planets. That is the difference. So far quality is concerned, both of them are spiritual, oṁkāra or Hare Kṛṣṇa. So; bhāgavatārambhe vyāsa maṅgalācaraṇe, 'parameśvara' nirūpila ei dui lakṣaṇe (CC Madhya 20.358).