Śrī Caitanya Mahāprabhu has given us an authorized program for this purpose, centered around the chanting of the Hare Kṛṣṇa mantra. This chanting has so much power that it immediately attaches one to Kṛṣṇa. That is the beginning of sādhana-bhakti. Somehow or other, one has to fix his mind on Kṛṣṇa. The great saint Ambarīṣa Mahārāj, although a responsible king, fixed his mind on Kṛṣṇa, and similarly anyone who tries to fix his mind in this way will very rapidly make progress in successfully reviving his original Kṛṣṇa consciousness.
Now this sādhana-bhakti, or practice of devotional service, can also be divided into two parts. The first part is called regulative principles: one has to follow these different regulative principles by the order of the spiritual master, or on the strength of authoritative scriptures, and there can be no question of refusal. That is called vaidhi, or regulated. One has to do it without any argument. Another part of sādhana-bhakti is called rāgānugā. Rāgānugā refers to the point at which, by following the regulative principles, one becomes a little more attached to Kṛṣṇa and executes devotional service out of natural love. For example, a person engaged in devotional service may be ordered to rise early in the morning and offer ārātrika, which is a form of Deity worship. In the beginning, by the order of his spiritual master, one rises early in the morning and offers ārātrika, but then he develops real attachment. When he gets this attachment, he automatically tries to decorate the Deity and prepare different kinds of dresses and thinks of different plans to execute his devotional service nicely. Although it is within the category of practice, this offering of loving service is spontaneous. So the practice of devotional service, sādhana-bhakti, can be divided into two parts—namely, regulative and spontaneous.
Rūpa Gosvāmī defines the first part of devotional practice, or vaidhi-bhakti, as follows: "When there is no attachment or no spontaneous loving service to the Lord, and one is engaged in the service of the Lord simply out of obedience to the order of the spiritual master or in pursuance of the scriptures, such obligatory service is called vaidhi-bhakti."
These principles of vaidhi-bhakti are also described in the Śrīmad-Bhāgavatam, Second Canto, 1st Chapter, verse 35, where Śukadeva Gosvāmī instructs the dying Mahārāj Parīkṣit as to his course of action. Mahārāj Parīkṣit met Śukadeva Gosvāmī just a week before his death, and the King was perplexed as to what should be done before he was to pass on. Many other sages also arrived there, but no one could give him the proper direction. Śukadeva Gosvāmī, however, gave this direction to him as follows: "My dear King, if you want to be fearless in meeting your death next week (for actually everyone is afraid at the point of death), then you must immediately begin the process of hearing and chanting and remembering God." If one can chant and hear Hare Kṛṣṇa and always remember Lord Kṛṣṇa, then he is sure to become fearless of death, which may come at any moment.
In the statements of Śukadeva Gosvāmī it is said that the Supreme Personality of Godhead is Kṛṣṇa. Therefore Śukadeva recommends that one should always hear about Kṛṣṇa. He does not recommend that one hear and chant about the demigods. The māyāvādīs (impersonalists) say that you can chant any name, either that of Kṛṣṇa or those of the demigods, and the result will be the same. But actually this is not a fact. According to the authorized version of Śrīmad-Bhāgavatam, one has to hear and chant about Lord Viṣṇu (Kṛṣṇa) only.
So Śukadeva Gosvāmī has recommended to Parīkṣit Mahārāj that in order to be fearless of death one has to hear and chant and remember the Supreme Personality of Godhead, Kṛṣṇa, by all means. He also mentions that the Supreme Personality of Godhead is sarvātmā. Sarvātmā means "the supersoul of everyone." Kṛṣṇa is also mentioned as īśvara, the supreme controller who is situated in everyone's heart. Therefore, if some way or other we become attached to Kṛṣṇa, He will make us free from all danger. In the Bhagavad-gītā it is said that anyone who becomes a devotee of the Lord is never vanquished. Others, however, are always vanquished. Vanquished means that after getting this human form of life, a person does not come out of the entanglement of birth and death and thus misses his golden opportunity. Such a person does not know where he is being thrown by the laws of nature.