Of the saintly persons who are constantly engaged in striving toward salvation, one who is in Kṛṣṇa consciousness is the best of all. The Bhāgavatam (4.22.39) confirms this fact as follows:
yat-pāda-paṅkaja-palāśa-vilāsa-bhaktyā
karmāśayaṁ grathitam udgrathayanti santaḥ
tadvan na rikta-matayo yatayo 'pi ruddha-
sroto-gaṇās tam araṇaṁ bhaja vāsudevam
"Just try to worship, in devotional service, Vāsudeva, the Supreme Personality of Godhead. Even great sages are not able to control the forces of the senses as effectively as those who are engaged in transcendental bliss by serving the lotus feet of the Lord, uprooting the deep-grown desire for fruitive activities." In the conditioned soul the desire to enjoy the fruitive results of work is so deep rooted that it is very difficult even for the great sages to control such desires, despite great endeavors. A devotee of the Lord, constantly engaged in devotional service in Kṛṣṇa consciousness, perfect in self-realization, very quickly attains liberation in the Supreme. Owing to his complete knowledge in self-realization, he always remains in trance.
(Bhagavad-Gita----5:26----purport).

Since this temporary material world is full of the miseries of birth, old age, disease and death, naturally he who achieves the highest perfection and attains the supreme planet, Kṛṣṇaloka, Goloka Vṛndāvana, does not wish to return. The supreme planet is described in Vedic literature as avyakta and akṣara and paramā gati; in other words, that planet is beyond our material vision, and it is inexplicable, but it is the highest goal, the destination for the mahātmās (great souls). The mahātmās receive transcendental messages from the realized devotees and thus gradually develop devotional service in Kṛṣṇa consciousness and become so absorbed in transcendental service that they no longer desire elevation to any of the material planets, nor do they even want to be transferred to any spiritual planet. They only want Kṛṣṇa and Kṛṣṇa's association, and nothing else. That is the highest perfection of life. This verse specifically mentions the personalist devotees of the Supreme Lord, Kṛṣṇa. These devotees in Kṛṣṇa consciousness achieve the highest perfection of life. In other words, they are the supreme souls.
(Bhagavad-Gita----8:15----purport).

The conclusion of Bhagavad-gītā is stated in the Eighteenth Chapter:
sarva-dharmān parityajya
mām ekaṁ śaraṇaṁ vraja
ahaṁ tvāṁ sarva-pāpebhyo
mokṣayiṣyāmi mā śucaḥ
[Bg. 18.66]
One should give up all other processes of self-realization and simply execute devotional service in Kṛṣṇa consciousness. That will enable one to reach the highest perfection of life. There is no need for one to consider the sinful actions of his past life, because the Supreme Lord fully takes charge of him. Therefore one should not futilely try to deliver himself in spiritual realization. Let everyone take shelter of the supreme omnipotent Godhead, Kṛṣṇa. That is the highest perfection of life.
(Bhagavad-Gita----12:6-7----purport).

In summary, to reach the Supreme Personality of Godhead, the highest goal, there are two processes: one process is by gradual development, and the other process is direct. Devotional service in Kṛṣṇa consciousness is the direct method, and the other method involves renouncing the fruits of one's activities. Then one can come to the stage of knowledge, then to the stage of meditation, then to the stage of understanding the Supersoul, and then to the stage of the Supreme Personality of Godhead. One may take either the step-by-step process or the direct path. The direct process is not possible for everyone; therefore the indirect process is also good. It is, however, to be understood that the indirect process is not recommended for Arjuna, because he is already at the stage of loving devotional service to the Supreme Lord. It is for others, who are not at this stage; for them the gradual process of renunciation, knowledge, meditation and realization of the Supersoul and Brahman should be followed. But as far as Bhagavad-gītā is concerned, it is the direct method that is stressed. Everyone is advised to take to the direct method and surrender unto the Supreme Personality of Godhead, Kṛṣṇa.
(Bhagavad-Gita----12:12----purport).

How one can stay in the transcendental position, even in this body, in full Kṛṣṇa consciousness, is explained in this verse. The Sanskrit word dehī means "embodied." Although one is within this material body, by his advancement in spiritual knowledge he can be free from the influence of the modes of nature. He can enjoy the happiness of spiritual life even in this body because, after leaving this body, he is certainly going to the spiritual sky. But even in this body he can enjoy spiritual happiness. In other words, devotional service in Kṛṣṇa consciousness is the sign of liberation from material entanglement, and this will be explained in the Eighteenth Chapter. When one is freed from the influence of the modes of material nature, he enters into devotional service.
(Bhagavad-Gita----14:20----purport).

Persons who have not undergone the austerities of the religious process, who have never attempted devotional service in Kṛṣṇa consciousness, who have not tended a pure devotee, and especially those who are conscious of Kṛṣṇa only as a historical personality or who are envious of the greatness of Kṛṣṇa should not be told this most confidential part of knowledge. It is, however, sometimes found that even demoniac persons who are envious of Kṛṣṇa, worshiping Kṛṣṇa in a different way, take to the profession of explaining Bhagavad-gītā in a different way to make business, but anyone who desires actually to understand Kṛṣṇa must avoid such commentaries on Bhagavad-gītā. Actually the purpose of Bhagavad-gītā is not understandable to those who are sensuous. Even if one is not sensuous but is strictly following the disciplines enjoined in the Vedic scripture, if he is not a devotee he also cannot understand Kṛṣṇa. And even when one poses himself as a devotee of Kṛṣṇa but is not engaged in Kṛṣṇa conscious activities, he also cannot understand Kṛṣṇa.
(Bhagavad-Gita----18:67----purport).

Devotional service in Kṛṣṇa consciousness cannot be performed blindly due to material emotion or mental concoction. It is specifically mentioned here that one has to perform devotional service in full knowledge by visualizing the Absolute Truth. We can understand about the Absolute Truth by evolving transcendental knowledge, and the result of such transcendental knowledge will be manifested by renunciation. That renunciation is not temporary or artificial, but is very strong. It is said that development of Kṛṣṇa consciousness is exhibited by proportionate material detachment, or vairāgya. If one does not separate himself from material enjoyment, it is to be understood that he is not advancing in Kṛṣṇa consciousness. Renunciation in Kṛṣṇa consciousness is so strong that it cannot be deviated by any attractive illusion. One has to perform devotional service in full tapasya, austerity. One should fast on the two Ekādaśī days, which fall on the eleventh day of the waxing and waning moon, and on the birthdays of Lord Kṛṣṇa, Lord Rāma and Caitanya Mahāprabhu. There are many such fasting days. Yogena means "by controlling the senses and mind." Yoga indriya-saṁyamaḥ. Yogena implies that one is seriously absorbed in the self and is able, by development of knowledge, to understand his constitutional position in relationship with the Superself. In this way one becomes fixed in devotional service, and his faith cannot be shaken by any material allurement.
(Srimad Bhagavatam----3:27:22----purport).

Another significant point of this verse is that one has to observe the prescribed rules and regulations. As confirmed in Bhagavad-gītā, yuktāhāra-vihārasya. When one engages in devotional service in Kṛṣṇa consciousness, he still has to eat, sleep, defend and mate because these are necessities of the body. But he performs such activities in a regulated way. He has to eat kṛṣṇa-prasāda. He has to sleep according to regulated principles. The principle is to reduce the duration of sleep and to reduce eating, taking only what is needed to keep the body fit. In short, the goal is spiritual advancement, not sense gratification. Similarly, sex life must be reduced. Sex life is meant only for begetting Kṛṣṇa conscious children. Otherwise, there is no necessity for sex life. Nothing is prohibited, but everything is made yukta, regulated, with the higher purpose always in mind. By following all these rules and regulations of living, one becomes purified, and all misconceptions due to ignorance become nil. It is specifically mentioned here that the causes of material entanglement are completely vanquished.
(Srimad Bhagavatam----3:33:26----purport).

Lord Caitanya thus explained briefly the transcendental situation and spiritual enjoyment of life, and He taught that the first stage of perfection is to become a religious man in the ordinary sense, as known in the material world. The second stage of perfection is to become materially rich. The third stage of material perfection is the attainment of complete sense enjoyment, and in the fourth stage there is knowledge of liberation. Above this platform are those on the fifth stage who are already liberated and who are established in Kṛṣṇa consciousness or devotional service to the Lord. In the highest perfection of devotional service in Kṛṣṇa consciousness, one experiences the taste of the ecstasy of spiritual relish.
(Teachings of Lord Caitanya).

As long as one identifies himself as belonging to a certain family, a certain society or a certain person, he is said to be covered with designations. When one is fully aware that he does not belong to any family, society or country, but is eternally related to Kṛṣṇa, he then realizes that his energy should be employed not in the interests of so-called family, society or country, but in the interests of Kṛṣṇa. This is purity of purpose and the platform of pure devotional service in Kṛṣṇa consciousness.
(Nectar of devotion).

Actually, a pure devotee does not aspire after any of these perfections, because the happiness derived from devotional service in Kṛṣṇa consciousness is so transcendental and so unlimited that no other happiness can compare to it. It is said that even one drop of happiness in Kṛṣṇa consciousness stands beyond comparison with an ocean of happiness derived from any other activity. Thus, any person who has developed even a little quantity of pure devotional service can very easily kick out all the other kinds of happiness derived from religiousness, economic development, sense gratification and liberation.
(Nectar of devotion).