Without being fearless, one cannot be joyful

From the Purport to SB 4.24.52

In Bhagavad-gītā it is said that in order to make spiritual progress, one must become fearless. Abhayaṁ sattva-saṁśuddhiḥ (Bg. 16.1). Fearfulness is the result of material involvement. It is also said in Śrīmad-Bhāgavatam(11.2.37), bhayaṁ dvitīyābhiniveśataḥ syāt: fearfulness is a creation of the bodily conception of life. As long as one is absorbed in the thought that he is this material body, he is fearful, and as soon as one is freed from this material conception, he becomes brahma-bhūta, or self-realized, and immediately becomes fearless. Brahma-bhūtaḥ prasannātmā (Bg. 18.54). Without being fearless, one cannot be joyful. The bhaktas, the devotees, are fearless and always joyful because they are constantly engaged in the service of the lotus feet of the Lord. It is also said:

evaṁ prasanna-manaso
 bhagavad-bhakti-yogataḥ
bhagavat-tattva-vijñānaṁ
 mukta-saṅgasya jāyate

(Bhāg. 1.2.20)

By practicing bhagavad-bhakti-yoga, one becomes fearless and joyful. Unless one becomes fearless and joyful, he cannot understand the science of God. Bhagavat-tattva-vijñānaṁ mukta-saṅgasya jāyate. This verse refers to those who are completely liberated from the fearfulness of this material world. When one is so liberated, he can really understand the transcendental features of the form of the Lord. Lord Śiva therefore advises everyone to practicebhagavad-bhakti-yoga. As will be clear in the following verses, by doing so one can become really liberated and enjoy spiritual bliss.

It is also stated:

om ajñāna-timirāndhasya
 jñānāñjana-śalākayā
cakṣur unmīlitaṁ yena
 tasmai śrī-gurave namaḥ

The Lord is the supreme spiritual master, and the bona fide representative of the Supreme Lord is also a spiritual master. The Lord from within enlightens the devotees by the effulgence of the nails of His lotus feet, and His representative, the spiritual master, enlightens from without. Only by thinking of the lotus feet of the Lord and always taking the spiritual master’s advice can one advance in spiritual life and understand Vedic knowledge:

yasya deve parā bhaktir
 yathā deve tathā gurau
tasyaite kathitā hy arthāḥ
 prakāśante mahātmanaḥ

Thus the Vedas (Śvetāśvatara Upaniṣad 6.23) enjoin that for one who has unflinching faith in the lotus feet of the Lord, as well as in the spiritual master, the real import of Vedic knowledge can be revealed.