Bhagavad-Gita: Chapter 4, Verse 39

Rudra Vaisnava Sampradaya:

Visnuswami

Sridhara Swami's Commentary

The person with faith who follows the Vedic instructions of the spiritual master and who wholeheartedly believes in the knowledge of the Vedic scriptures and who is self-controlled; only such a person receives spiritual realisation and none other. Therefore before ones receives spiritual knowledge through the auspices of faith one has to undergo the path of karma yoga or performance of prescribed Vedic activities for one's purification. After spiritual realisation is attained then one has become mukta or liberated and has no need to perform any action.

Brahma Vaisnava Sampradaya:

Madhvacarya
There is no commentary for this verse.

Sri Vaisnava Sampradaya:

Ramanuja

Ramanuja's Commentary

Receiving knowledge by instructions of the spiritual master becoming more and more devoted and evolved as the process develops and becoming more and more detached from external affairs away from where the sense objects are exerting there influence one will invariably reach the pinnacle of wisdom and attain moksa or liberation from the material existence.

Kumara Vaisnava Sampradaya:

Nimbaditya

Kesava Kasmiri's Commentary

One might speculate that if one can achieve purity of heart through the practice of karma yoga or prescribed Vedic activities and hence acquire knowledge by this effort then what is the necessity for approaching a spiritual master as spoken of in verse thirty four? To lay this doubt to rest Lord Krishna specifically states who is qualified to receive spiritual knowledge. A person may acquire knowledge by themselves but here are presented all the qualities that are essential for such a person to succeed. The word sraddhavan means a person who has faith. Faith is firmly believing. Believing is something that must have a source from where it believed in. Verily that source is the words of the spiritual master who reveals the inner meaning of the Vedic scriptures by explaining them in an way that is easy to understand. But this is not enough there must also be sincere devoted service to the spiritual master while studying the Vedic scriptures under his tutelage. But there is more one must also avoid the association of those who are not following the Vedic injunctions as association with them may cause one to deviate from the path of knowledge in spite of having faith and be captivated once again by maya or illusion neglecting to study the Vedic scriptures and omitting to serve the spiritual master. So only one who is self-controlled attains spiritual knowledge and acquiring such knowledge one neutralises all extraneous activities and perceives the Brahman or the spiritual substratum pervading all existence and from there achieves atma tattva or soul realisation and from that platform attains moksa or liberation from material existence. So a person of faith must follow the age old process in the proper sequence to attain the coveted goal.