To take shelter of the lotus feet of the Lord means to take shelter of the pure devotees. The pure devotees whose only business is serving are honored by the names Prabhupāda and Viṣṇupāda, which indicate such devotees to be representatives of the lotus feet of the Lord. Anyone, therefore, who takes shelter of the lotus feet of a pure devotee by accepting the pure devotee as his spiritual master can be at once purified. Such devotees of the Lord are honored equally with the Lord because they are engaged in the most confidential service of the Lord, for they deliver out of the material world the fallen souls whom the Lord wants to return home, back to Godhead. Such pure devotees are better known as vicelords according to revealed scriptures. The sincere disciple of the pure devotee considers the spiritual master equal to the Lord, but always considers himself to be a humble servant of the servant of the Lord (cc.2:13:80). This is the pure devotional path.
(Srimad Bhagavatam-----1:1:15----purport).

The spiritual master, the servant of God, is engaged in the most confidential service of the Lord, namely delivering all the conditioned souls from the clutches of māyā, in which one thinks, "This person is my enemy, and that one is my friend." Actually the Supreme Personality of Godhead is the friend of all living entities, and all living entities are eternal servants of the Supreme Lord. Oneness is possible through this understanding, not through artificially thinking that every one of us is God or equal to God. The true understanding is that God is the supreme master and that all of us are servants of the Supreme Lord and are therefore on the same platform. This had already been taught to Prahlāda Mahārāja by his spiritual master, Nārada, but Prahlāda was nonetheless surprised by how a bewildered soul thinks one person his enemy and another his friend.
(Srimad Bhagavatam-----7:5:11----purport).

Once, after Rantideva spent forty-eight days fasting, not even drinking water, excellent food made with ghee was brought to him, but when he was about to eat it a brāhmaṇa guest appeared. Rantideva, therefore, did not eat the food, but instead immediately offered a portion of it to the brāhmaṇa. When the brāhmaṇa left and Rantideva was just about to eat the remnants of the food, a śūdra appeared. Rantideva therefore divided the remnants between the śūdra and himself. Again, when he was just about to eat the remnants of the food, another guest appeared. Rantideva therefore gave the rest of the food to the new guest and was about to content himself with drinking the water to quench his thirst, but this also was precluded, for a thirsty guest came and Rantideva gave him the water. This was all ordained by the Supreme Personality of Godhead just to glorify His devotee and show how tolerant a devotee is in rendering service to the Lord. The Supreme Personality of Godhead, being extremely pleased with Rantideva, entrusted him with very confidential service. The special power to render the most confidential service is entrusted by the Supreme Personality of Godhead to a pure devotee, not to ordinary devotees.
(Srimad Bhagavatam-----9:21--summary).

The Supreme Personality of Godhead, Lord Śrī Kṛṣṇa, after displaying His pastimes as Lord Kṛṣṇa, thought it wise to make His advent in the form of a devotee to explain personally the transcendental mellows of reciprocal service and love exchanged between Himself and His servants, friends, parents and fiancīes. According to the Vedic literature, the foremost occupational duty for humanity in this Age of Kali is nāma-saṅkīrtana, or congregational chanting of the holy name of the Lord. The incarnation for this age especially preaches this process, but only Kṛṣṇa Himself can explain the confidential loving service performed in the four principal varieties of loving affairs between the Supreme Lord and His devotees. Lord Kṛṣṇa therefore personally appeared, with His plenary portions, as Lord Caitanya. As stated in this chapter, it was for this purpose that Lord Kṛṣṇa appeared personally in Navadvīpa in the form of Śrī Kṛṣṇa Caitanya Mahāprabhu.
(Sri Caitanya Caritamrta----1:3--summary).

The devotee engages in the Lord's service in great ecstatic love. Such love was exhibited personally by Śrī Caitanya Mahāprabhu in His teachings to the people of the material world. The fruit of the devotional creeper is the pure desire to serve and please the senses of the Supreme Personality of Godhead. Kṛṣṇendriya-prīti-icchā dhare "prema" nāma. (Cc. Ādi. 4.165) In the spiritual world one has no desire other than to please the senses of the Supreme Personality of Godhead. The conditioned soul within the material world can neither understand nor appreciate how a pure devotee in the material world can render confidential service to the Lord out of feelings of ecstatic love and always engage in pleasing the Supreme Lord's senses. Although seen within this material world, the pure devotee always engages in the confidential service of the Lord. An ordinary neophyte devotee cannot realize this; therefore it is said, vaiṣṇavera kriyā-mudrā vijñeha nā bujhaya (cc.2:23:39). The activities of a pure Vaiṣṇava cannot be understood even by a learned scholar in the material world.
(Sri Caitanya Caritamrta----2:19:155).

Offering gifts in charity, accepting charitable gifts, revealing one's mind in confidence, inquiring confidentially, accepting prasāda and offering prasāda are the six symptoms of love shared by one devotee and another.
In this verse Śrīla Rūpa Gosvāmī explains how to perform devotional activities in the association of other devotees. There are six kinds of activities: (1) giving charity to the devotees, (2) accepting from the devotees whatever they may offer in return, (3) opening one's mind to the devotees, (4) inquiring from them about the confidential service of the Lord, (5) honoring prasāda, or spiritual food, given by the devotees, and (6) feeding the devotees with prasāda. An experienced devotee explains, and an inexperienced devotee learns from him. This is guhyam ākhyāti pṛcchati. When a devotee distributes prasāda, remnants of food offered to the Supreme Personality of Godhead, in order to maintain our spirit of devotional service we must accept this prasāda as the Lord's grace received through the pure devotees. We should also invite pure devotees to our home, offer them prasāda and be prepared to please them in all respects. This is called bhuṅkte bhojayate caiva.
(Nectar of Instruction).

Those who think that Kṛṣṇa consciousness is limited to a certain section of people, a certain section of devotees or a certain tract of land are generally prone to see the external features of the devotee. Such neophytes, unable to appreciate the exalted service of the advanced devotee, try to bring the mahā-bhāgavata to their platform. We experience such difficulty in propagating this Kṛṣṇa consciousness all over the world. Unfortunately we are surrounded by neophyte Godbrothers who do not appreciate the extraordinary activities of spreading Kṛṣṇa consciousness all over the world. They simply try to bring us to their platform, and they try to criticize us in every respect. We very much regret their naive activities and poor fund of knowledge. An empowered person who is actually engaged in the confidential service of the Lord should not be treated as an ordinary human being, for it is stated that unless one is empowered by Kṛṣṇa, one cannot spread the Kṛṣṇa consciousness movement all over the world.
(Nectar of Instruction).