One who wants to worship the Supreme Lord must first of all take shelter of the lotus feet of Śrī Guru. bhajana-sādhana is far removed from one who does not take shelter of the lotus feet of Śrī Guru, because this is the gate through which one enters the path of bhakti.
This does not only count for the path of bhakti, there is no practice in the world that does not require the shelter of a Guru’s (teacher’s) feet! If it is necesary to take a learned and experienced teacher to learn something in this mundane world, then it is needless to say that one needs a Guru to learn bhakti, which is the highest science in the spiritual world, from. Another special feature of devotional knowledge is that the merciful Śrī Bhagavān has personally appeared within this world in the form of the Guru to teach bhakti to the people of the world.

We have briefly discussed the Guru-principle above. When the gravity (gurutva) of the Guru-principle is understood, then there will be no more doubts about the importance of taking shelter of the lotus feet of Śrī Guru. What is the intrinsic status of Śrī Guru, what is the substance (essence) of Guru and what is the auspicious result of taking shelter of Śrī Guru’s feet — the ignorant person has different doubts about these questions regarding taking shelter of Śrī Guru’s feet. Knowledge on all these Guru-principles is acquired in the association of the sādhus.

Without the company of the devotees of the Supreme Lord, the principle of Guru cannot be understood. Hence the scriptures and the great saints first of all advise the people who wish to do sādhana bhajana and who desire the highest welfare, to associate with the saints. In Śrīmad Bhāgavata, Lord Śrī Kapiladeva has told His own mother Devahūti —

satāṁ prasaṅgān mama vīrya saṁvido bhavanti hṛt karṇa rasāyanāḥ kathāḥ taj joṣaṇād āśvapavarga vartmani śraddhā ratir bhaktir anukramiṣyati  (Bhāgavata 3.25.25)

“When one attains the excellent company of the saints, topics that indicate My glories become like nectar for the heart and the ears. Anyone who lovingly relishes these topics, that are the swift pathway to the cessation of ignorance, will gradually develop faith, attachment and devotion for Me.”

The purport of this is that by hearing topics on the Supreme Lord from the great saints, one first attains faith, then one attains the shelter of a bona fide Guru and engages in bhajana, as a result of which rati and prema gradually develop. By the Lord’s wish, the living beings have been wandering (reincarnating) through different species of life since beginningless time and by the Lord’s grace they have attained this human body, which is the gateway to liberation from the repetition of birth and death.

The most fortunate amongst these human beings will attain the association of the saints. While hearing topics of Śrī Kṛṣṇa from the mouths of the greatly realised devotees of the Lord, the heart, which is polluted by attachment to sense objects, will be somewhat purified and one will realise that the body and everything related to it is temporary, and the ocean of temporary material existence seems impossible to cross. Then, the heart will become eager to cross the impassable and miserable ocean of material existence, that is filled with the crocodiles and sharks of lust and anger, to attain the eternally blissful lotus feet of the Lord and to find a suitable captain for the sturdy ship of the human body — Śrī Guru. In Śrīmad Bhāgavata, Śrī Kṛṣṇa has told Uddhava —

nṛ deham ādyaṁ sulabhaṁ sudurlabhaṁ plavaṁ sukalpaṁ guru karṇa-dhāram mayānukūlena nabhasvateritaṁ pumān bhavābdhiṁ na taret sa ātma-hā  (Śrīmad Bhāgavata 11.20.17)

“O Uddhava! This human body is the ādya, the root cause of all welfare, and sukalpa, expert in accomplishing its goal. The living entity attains this rarely attained human body, which is like an excellent boat that has Śrī Gurudeva as its captain. On top of everything I am providing favorable winds to steer it in the right direction. A person who does not endeavour to cross the ocean of material existence despite receiving this body is destroying himself.”

We have already discussed that in the company of the saints one comes to realise that one must take shelter of the feet of a Guru. Thus we must understand that association with the bhaktas has not taken place if one has not realised the necessity of taking shelter of the feet of a Guru. Wherever the association of the devotees is attained or is going on and there is no realisation about the obligation to take shelter of the lotus feet of Śrī Guru, or such shelter has not yet been taken, we must understand that the real association of saints has not taken place yet, or that due to some mischief the results of association with the saints are not yet tangible. As long as the shelter of Śrī Guru’s lotus feet has not yet been attained, the ultimate fruits of association with the devotees will remain the shelter of Śrī Guru’s lotus feet, for only after taking initiation and instructions from the bona fide Guru, bhajana commences.

When a person wishes to be blessed with the fruits of sādhana bhajana and he desires to take shelter of the lotus feet of Śrī Guru, it is absolutely necessary that he takes shelter of the feet of a bona fide Guru. When the Guru-potency awakens within a saint he becomes known as a bona fide Guru.

This Guru-potency awakens within a saint in the following way – those who have removed the dirt from their hearts through their practice of sādhana bhajana; in whose hearts bhakti has awakened and who have become ornamented by saintly qualities such as compassion and kindness – their hearts melt when they see the misery the conditioned souls go through in the material world of māyā. By instructing the conditioned souls in the practice of bhajana, they destroy their miserable condition and they are eager to bless them by giving them the relish of bhakti rasa.

By the Lord’s wish, the Guru-potency emanates from Him and appears within the hearts of such bhakti siddha mahāpuruṣas (His pure devotees). A person who covets devotion to the Supreme Lord is blessed by taking shelter of such a qualified and bona fide Guru. The characteristics of such a bona fide Guru have been described in Śrīmad Bhāgavata (11.3.21) —

tasmād guruṁ prapadyeta jijñāsuḥ śreyaḥ uttamam śābde pare ca niṣṇātaṁ brahmaṇyupaśamāśrayam

“Therefore a person who inquires about the highest welfare should take shelter of the lotus feet of a bona fide Guru, who is śabda brahma and para brahma niṣṇāta and upaśamāśraya or free from lust and greed.”

Śrīdhara Svāmī writes in his commentary on this verse: śābde brahmaṇi vedākhye nyāyato niṣṇātaṁ tattvajñam. anyathā saṁśaya nirāsakatvāyogāt. pare ca brahmaṇi aparokṣānubhavena niṣṇātam. anyathā bodha sañcārāyogāt. para brahma niṣṇātatva dyotakam āha upaśamāśrayam iti — “That the bona fide Guru is śabda brahma niṣṇāta means that he is a knower of the Vedic literature and a knower of the truth. If he is not, then he cannot remove the doubts of the disciples that take shelter of him. Then again he is para brahma niṣṇāta, which means that He is a devotee, or that He is endowed with transcendental realisations about Śrī Kṛṣṇa. If he is not, then he cannot infuse realisations on bhajana within the heart of his disciple.”

One may ask here: “We may be able to see that the Guru is śabda brahma niṣṇāta by seeing and hearing his scriptural knowledge, but how will we know if he is para brahma niṣṇāta, or filled with transcendental realisations about Śrī Kṛṣṇa?” The answer to this is that he should be upaśamāśraya, or devoid of lust, anger and greed. The heart of anyone who is enlightened by bhakti cannot be covered by the darkness of lust and greed and so on. Therefore the definitions of a bona fide Guru given by the śāstras are as follows:

1) He is filled with realisations about the Personality of Godhead due to his firm faith and his firm adherence to the worship of the Lord. He has attained the grace of his own Guru by being similarly devoted to his Guru’s lotus feet.

2) He is very learned in the Vedas and in bhakti-scriptures that outline the Vedic purport such as Śrīmad Bhāgavata. Thus he can destroy the doubts in his disciples.

3) Because he has transcendental realisations about Śrī Kṛṣṇa, he has attained His mercy-potency. Thus he has become so powerful that he is able to bring the disciple onto the path of bhakti and infuse this power within him.

4) He is not overcome by vices like lust and greed.

A saint who is endowed with such attributes and who is filled with parental love for his disciples, can attain the position of a bona fide Guru. Such a bona fide Guru is able to destroy different obstacles the disciple may find in his bhajana, bless him with prema and bring him to the lotus feet of Śrī Kṛṣṇa. On the other hand, a person who desires to be known as a Guru may have many virtues, like high birth and so on, but if he does not have the above mentioned characteristics, he will not be counted amongst the bona fide Gurus. Therefore a faithful person who is eager to do Śrī Kṛṣṇa-bhajana should take shelter of the lotus feet of a mahā puruṣa who is endowed with the right qualities, receive initiation into Śrī Kṛṣṇa-mantra from him and learn bhajana from him.

Some people think that a bona fide Guru is very rare in this world and it is not easy to recognise and attain a bona fide Guru. Thinking like this, they do not endeavour to take dīkṣā-mantra and thus waste the precious moments of their rare human lives. In this connection it must be said that when the Lord descends as the bona fide Guru for the benefit of the world, He is never hard to attain or unattainable for the genuine seekers of bhajana and those who are eager to take shelter of the bona fide Guru.

Those who give up crookedness and associate with the saints with a simple and innocent mind, for the cessation of their material miseries, and earnestly take shelter of the feet of a bona fide Guru, for the sake of worshipping the Lord, praying to the Lord with an eager heart, while hoping to attain the bona fide Guru, will certainly be blessed with the shelter of a bona fide Guru — of this there is not even the slightest doubt. Merciful Śrī Hari will certainly provide good luck and opportunities to such people, who are so eager to do bhajana.

The first three of the 64 items of bhajana that are described by Śrīmat Rūpa Gosvāmīpāda are guru padāśrayas tasmāt kṛṣṇa dīkṣādi śikṣaṇam viśrambheṇa guroḥ sevā (Bhakti Rasāmṛta Sindhu 1.2.74)

1) Taking shelter of Śrī Guru’s feet

2) Taking initiation into Śrī Kṛṣṇa-mantra and learning Bhāgavata-dharma (the religion of worshipping the Personality of Godhead) from him

3) Serving Śrī Guru with faith. guru padāśraya, dīkṣā, gurura sevana (C.C.)

guru padāśraya means that a person who wishes to do bhagavad bhajana must live near Śrī Guru’s feet for a while before taking initiation, and sincerely render service to him according to his wishes, so that Śrī Guru’s lotus feet are pleased. In the scriptures, a mutual examination of Guru and disciple is also described as necessary. In this way both Guru and disciple can examine each other’s natures and qualifications. If this is not done then they may both experience obstacles in their bhajana in the future.

In other words, if the Guru does not have the characteristics that are described in the śāstras, the disciple will inevitably experience obstacles in bhajana and if the disciple is not qualified then the Guru will inevitably experience obstacles in bhajana. Not only that, this also has a very valuable result. When the sādhaka who is eager to receive dīkṣā stays for a few days with the Guru and engages in his service he will also become qualified for both dīkṣā and bhajana. On the other hand, the Śrī Guru-principle will melt with compassion when he sees the sincere service rendered to such a mahā bhāgavata (great devotee). The practising devotee fulfills a main human pursuit by attaining the dīkṣā mantra from the lotus feet of Śrī Guru, whose heart is melting of compassion, being satisfied with his service. In this way the practising devotee will be blessed with the true relish of ambrosial bhakti rasa.

Here it is noteworthy that a mahā puruṣa, who is endowed with extraordinary powers, can examine the qualifications of a disciple on mere sight, or can make an unqualified candidate at once qualified and can thus give initiation to a candidate at once. For such great persons there is no bondage to the above rules and regulations. This, however, does not apply to all ordinary persons.

(Srila Ananta das Babaji)