When situated in the transcendental position, one is freed from the two kinds of material diseases—hankering and lamentation. This is also stated in Bhagavad-gītā. After devotional life begins, we can achieve the full result of love of Godhead. Love of Kṛṣṇa is the highest perfection of bhagavat-prasāda, or divine mercy. This transcendental achievement is so greatly valuable that no material happiness can compare to it.
(Srimad Bhagavatam----3:23:7----purport).

Service in Kṛṣṇa consciousness is, however, best practiced under the able guidance of a spiritual master who is a bona fide representative of Kṛṣṇa, who knows the nature of the student and who can guide him to act in Kṛṣṇa consciousness. As such, to be well versed in Kṛṣṇa consciousness one has to act firmly and obey the representative of Kṛṣṇa, and one should accept the instruction of the bona fide spiritual master as one's mission in life. Śrīla Viśvanātha Cakravartī Ṭhākura instructs us, in his famous prayers for the spiritual master, as follows:
yasya prasādād bhagavat-prasādo
yasyāprasādān na gatiḥ kuto 'pi
dhyāyan stuvaṁs tasya yaśas tri-sandhyaṁ
vande guroḥ śrī-caraṇāravindam
"By satisfaction of the spiritual master, the Supreme Personality of Godhead becomes satisfied. And by not satisfying the spiritual master, there is no chance of being promoted to the plane of Kṛṣṇa consciousness. I should, therefore, meditate and pray for his mercy three times a day, and offer my respectful obeisances unto him, my spiritual master."
(Bhagavad-Gita----2:41----purport).

By pleasing the spiritual master, who is a pure Vaiṣṇava, one pleases the Personality of Godhead, but if one displeases the spiritual master one does not know where he is going.
(Srimad Bhagavatam----4:9:23----purport).

It is said that the Lord is most pleased when He sees one engage in the service of His devotee. He does not need any service from anyone because He is complete, but it is in our own interest to offer all kinds of services to the Supreme Personality of Godhead. These services can be offered to the Supreme Person not directly but through the service of brāhmaṇas and Vaiṣṇavas.
(Srimad Bhagavatam----4:21:39----purport).

By pleasing the spiritual master, who is both brāhmaṇa and Vaiṣṇava, one pleases the Supreme Personality of Godhead. If the Supreme Personality of Godhead is pleased, then one has nothing more to achieve either in this world or after death.
(Srimad Bhagavatam----4:22:8----purport).

A disciple should always remember that by serving the spiritual master he can easily advance in Kṛṣṇa consciousness.
(Srimad Bhagavatam----4:28:34----purport).

If one wants actual success in life, he must strictly follow the instructions of the spiritual master. By following such instructions, one is sure to make rapid progress in spiritual life.
(Srimad Bhagavatam----4:28:65----purport).

If one always follows the orders of the spiritual master, there is no question of falling down. As soon as a foolish disciple tries to overtake his spiritual master and becomes ambitious to occupy his post, he immediately falls down.
(Srimad Bhagavatam----5:12:14----purport).

One must come to Kṛṣṇa consciousness, and therefore one must take shelter of a pure devotee. Thus one can become free from the clutches of matter.
(Srimad Bhagavatam----5:14:41----purport).

A Vaiṣṇava sees other servants to be so advanced that he has much to learn from them. Thus he accepts all other devotees of the Lord as prabhus, masters. Although everyone is a servant of the Lord, one Vaiṣṇava servant, because of humility, sees another servant as his master. Understanding of the master begins from understanding of the spiritual master.
(Srimad Bhagavatam----7:5:11----purport).

By the pleasure of the spiritual master, one can get extraordinary power, especially in spiritual advancement. The blessings of the spiritual master are more powerful than one's personal endeavor for such advancement.
(Srimad Bhagavatam----8:15:28----purport).

By the grace of a Vaiṣṇava or bona fide spiritual master one can get both love of Godhead, Kṛṣṇa, and Kṛṣṇa Himself.
(Sri Caitanya Caritamrta----1:11:59----purport).