śraddhāvāḻ labhate jñānaḿ
tat-paraḥ saḿyatendriyaḥ
jñānaḿ labdhvā parāḿ śāntim

Translation of Bhagavad Gita 4.39

A faithful man who is dedicated to transcendental knowledge and who subdues his senses is eligible to achieve such knowledge, and having achieved it he quickly attains the supreme spiritual peace.

Commentary by Sri A.C. Bhaktivedanta Swami Prabhupada of Gaudiya Sampradaya:

Such knowledge in Krishna consciousness can be achieved by a faithful person who believes firmly in Krishna. One is called a faithful man who thinks that simply by acting in Krishna consciousness he can attain the highest perfection. This faith is attained by the discharge of devotional service, and by chanting Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare, which cleanses one’s heart of all material dirt. Over and above this, one should control the senses. A person who is faithful to Krishna and who controls the senses can easily attain perfection in the knowledge of Krishna consciousness without delay.

Commentary by Sri Vishvanatha Chakravarthi Thakur of Gaudiya Sampradaya:

How and when does this happen? Having faith in the meaning of the scriptures that knowledge will arise by purity of heart through practice of niskama karma (sraddhavan), being fixed in execution of that niskama karma yoga, and finally attaining controlled senses, he will attain knowledge and supreme peace, meaning destruction of samsara.

Commentary by Sri Ramanuja of Sri Sampradaya:

4.39 After attaining knowledge through instruction in the manner described, he must have firm faith in it and the possibility of its development into ripe knowledge. He must be intent on it, i.e., his mind must be focussed thereupon. He must control his senses and keep them away from all their objects. Soon will he then reach the aforesaid state of maturity and obtain knowledge. Soon after attaining such kind of knowledge, he will reach supreme peace, i.e., he attains the supreme Nirvana (realisation of the self).

Commentary by Sri Sridhara Swami of Rudra Sampradaya:

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.

Commentary by Sri Madhvacharya of Brahma Sampradaya:

Sri Madhvacharya did not comment on this sloka.

Commentary by Sri Keshava Kashmiri of Kumara Sampradaya:

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.

Commentary by Sri Adi Shankaracharya of Advaita Sampradaya:

4.39 Sraddhavan, the man who has faith; labhate, attains; jnanam, Knowledge. Even when one has faith, he may be indolent. Therefore the Lord says, tatparah, who is diligent, steadfast in the service of the teacher, etc., which are the means of attaining Knowledge. Even when one has faith and is diligent, one may not have control over the organs. Hence the Lord says, samyata-indriyah, who has control over the organs-he whose organs (indriyani) have been withdrawn (samyata) from objects. He who is such, who is full of faith, diligent, and has control over the organs, does surely attain Knowledge. However, prostrations etc., which are external, are not invariably fruitful, for there is scope for dissimulation faith etc. But this is not so in the case of one possessing faith etc. Hence they are the unfailing means of acquiring Knowledge. What, again, will result from gaining Knowledge? This is being answered: Labdhva, achieving; jnanam, Knowledge; adhigacchati, one attains; acirena, soon indeed; param, supreme; santim, Peace, supreme detachment called Liberation. That Liberation soon follows from full Knowledge is a fact well ascertained from all the scriptures and reasoning. One should not entertain any doubt in this matter. For doubt is the most vicious thing. Why? The answer is being stated:

Commentary by Sri Abhinavagupta of Kaula Tantra Sampradaya:

4.39-40 Sraddhavan etc. Ajnah etc. Here the idea of the passage is this : The incoming of faith and the performance of activities intending this [knowledge], both spring up soon no doubt, if one, being a believer, entertains no doubt. Therefore, one should remain being favoured by the preceptors and the scriptures, and not entertaining any doubt. For, the doubt is a destroyer of everything [good]. Indeed a person with doubt knows nothing, because he does not have faith. Hence one should remain without doubt. The subject matter that has been elaborated in this entire chapter is now summarised by a pair of the [following] verses :

Sanskrit Shloka Without Transliteration Marks:

sraddhavaḻ labhate jñanam
tat-parah samyatendriyah
jñanam labdhva param santim

Sanskrit to English Word for Word Meanings:

śraddhā-vān — a faithful man; labhate — achieves; jñānam — knowledge; tat-paraḥ — very much attached to it; saḿyata — controlled; indriyaḥ — senses; jñānam — knowledge; labdhvā — having achieved; parām — transcendental; śāntim — peace; acireṇa — very soon; adhigacchati — attains.