In the Ādi Purāṇa, in a conversation between Kṛṣṇa and Arjuna, it is said, bhaktānām anugacchanti muktayaḥ śrutibhiḥ saha: “The most exalted position of liberation is given by Vedic knowledge. Everyone follows in the footsteps of the devotee.” Similarly, in the Bṛhan-nāradīya Purāṇa it is further stated, adyāpi ca muni-śreṣṭhā brahmādyā api devatāḥ: “Until now, even the great demigods like Brahmā and Lord Śiva did not know the influence of a devotee.” The Garuḍa Purāṇa similarly states:
brāhmaṇānāṁ sahasrebhyaḥ satra-yājī viśiṣyate
satra-yājī-sahasrebhyaḥ sarva-vedānta-pāragaḥ
sarva-vedānta-vit-koṭyā viṣṇu-bhakto viśiṣyate
vaiṣṇavānāṁ sahasrebhya ekānty eko viśiṣyate
“It is said that out of thousands of brāhmaṇas, one is qualified to perform sacrifices, and out of many thousands of such qualified brāhmaṇas expert in sacrificial offerings, one learned brāhmaṇa may have passed beyond all Vedic knowledge. He is considered the best among all these brāhmaṇas. And yet, out of thousands of such brāhmaṇas who have surpassed Vedic knowledge, one person may be a viṣṇu-bhakta, and he is most famous. Out of many thousands of such Vaiṣṇavas, one who is completely fixed in the service of Lord Kṛṣṇa is most famous. Indeed, a person who is completely devoted to the service of the Lord certainly returns home, back to Godhead.”
(Sri Caitanya Caritamrta-----2:8:246-----purport).

In the Ādi Purāṇa the Supreme Personality of Godhead Himself says:
na tathā me priyatamo brahmā rudraś ca pārthiva
na ca lakṣmīr na cātmā ca yathā gopī-jano mama
“Lord Brahmā, Lord Śiva, the goddess of fortune and even My own self are not as dear to Me as the gopīs.” Of all the gopīs, Śrīmatī Rādhārāṇī is the topmost. Rūpa Gosvāmī and Sanātana Gosvāmī are the most exalted servitors of Śrīmatī Rādhārāṇī and Lord Śrī Caitanya Mahāprabhu. Those who adhere to their service are known as rūpānuga devotees.
(Sri Caitanya Caritamrta-----2:8:246-----purport).

The Āditya Purāṇa, Mārkaṇḍeya Purāṇa and Padma Purāṇa tell about a brāhmaṇa who was suffering from leprosy but had a very chaste and faithful wife. He desired to enjoy the company of a prostitute, and therefore his wife went to her and became her maidservant, just to draw her attention for his service. When the prostitute agreed to associate with him, the wife brought her the leprotic husband. When that leper, the sinful son of a brāhmaṇa, saw the chastity of his wife, he finally abandoned his sinful intentions. While coming home, however, he touched the body of Mārkaṇḍeya Ṛṣi, who thus cursed him to die at sunrise. Because of her chastity, the woman was very powerful. Therefore when she heard about the curse, she vowed to stop the sunrise. Because of her strong determination to serve her husband, the three deities—namely Brahmā, Viṣṇu and Maheśvara—were very happy, and they gave her the benediction that her husband would be cured and brought back to life. This example is given herein to emphasize that a devotee should engage himself exclusively for the satisfaction of Kṛṣṇa, without personal motives. That will make his life successful.
(Sri Caitanya Caritamrta-----3:20:57-----purport).

In the Ādi Purāṇa it is said that liberation and transcendental life follow all the devotees of God.
(Teachings of Lord Caitanya).

In the Ādi Purāṇa there is the following statement by Lord Kṛṣṇa Himself, addressed to Arjuna: "My dear Pārtha, one who claims to be My devotee is not so. Only a person who claims to be the devotee of My devotee is actually My devotee." No one can approach the Supreme Personality of Godhead directly [Cc. Madhya 13.80]. One must approach Him through His pure devotees. Therefore, in the system of Vaiṣṇava activities, the first duty is to accept a devotee as spiritual master and then to render service unto him.
(Nectar of Devotion).

It is said in the Ādi Purāṇa, "A person who is constantly engaged in chanting the holy name and who feels transcendental pleasure, being engaged in devotional service, is certainly awarded the facilities of devotional service and is never given just mukti [liberation]." Mukti means liberation from material contamination; when liberated, one does not have to take birth again in the material world. The impersonalists desire to merge into the spiritual existence, to end their individual existence, but according to Śrīmad-Bhāgavatam, mukti is only the beginning of one's becoming situated in his normal condition. The normal condition of every living entity is to be engaged in the devotional service of the Lord. From the statement of the Ādi Purāṇa it appears that a devotee is satisfied simply with being engaged in devotional service. He does not aspire for any liberation from material, conditional life. In other words, anyone who is engaged in devotional service is not in the material condition of life, although he may appear so.
(Nectar of Devotion).

The importance of chanting Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare is very strongly stressed in the Second Canto, First Chapter, verse 11, of Śrīmad-Bhāgavatam in the following way. Śukadeva Gosvāmī tells Mahārāja Parīkṣit, "My dear King, if one is spontaneously attached to the chanting of the Hare Kṛṣṇa mahā-mantra, it is to be understood that he has attained the highest perfectional stage." It is specifically mentioned that the karmīs who are aspiring after the fruitive results of their activities, the salvationists who are aspiring to become one with the Supreme Person, and the yogīs who are aspiring after mystic perfections can achieve the results of all perfectional stages simply by chanting the mahā-mantra. Śukadeva uses the word nirṇītam, which means "it has already been decided." He was a liberated soul and therefore could not accept anything which was not conclusive. So Śukadeva Gosvāmī especially stresses that it has already been concluded that one who has come to the stage of chanting the Hare Kṛṣṇa mantra with determination and steadiness must be considered to have already passed the trials of fruitive activities, mental speculation and mystic yoga. The same thing is confirmed in the Ādi Purāṇa by Kṛṣṇa. While addressing Arjuna He says, "Anyone who is engaged in chanting My transcendental name must be considered to be always associating with Me. And I may tell you frankly that for such a devotee I become easily purchased."
(Nectar of Devotion).