A well-deliberated faith is the first qualification to rapidly enter into the mystery of transcendental knowledge. A faithful person gains knowledge (śraddhāvāḻ labhate jñānaṁ) by being dedicated to it (tat-paraḥ) with senses fully controlled (saṁyatendriyaḥ). Upon gaining such knowledge (jñānaṁ labdhvā), one quickly attains (acireṇādhigacchati) the supreme spiritual peace (parāṁ śāntim). (BG 4.39)

On the other hand (ca), an ignorant (ajñaś), faithless (cāśraddadhānaś), and doubting soul (saṁśayātmā) goes nowhere (vinaśyati). For the doubting soul (saṁśayātmanaḥ), there is (asti) no happiness (na sukhaṁ) – neither (na) in this world (ayaṁ loko) nor (na) in the next (paro). (BG 4.40)

An unfounded doubt is as perilous as blind faith. According to BG 4.40, three categories of people fall short of receiving transcendental knowledge:

• Ignorant (ajña): who have never contacted scriptures and hence perpetuate their ignorant condition.
• Faithless (aśraddadha): who have access to scriptures but don’t have any faith in them.
• Doubters (saṁśayātmā): who have some faith in the scriptures but remain disconnected from the conclusions of scriptures (such as Krishna’s position as God, or bhakti yoga as the recommended process for perfection) and therefore don’t apply the teachings.

The predicament of the doubters is most precarious as they thwart all the opportunities for progress that are in front of them and embrace endless suffering.

How can we destroy this doubt once and for all? It is possible by putting the transcendental knowledge into practice –– in dutiful (karmāṇaṁ), detached (sannyasta), and devotional (yoga) mood.

Actions (karmāṇi) don’t (na) bind (nibadhnanti ) one who has renounced actions through yoga (yoga-sannyasta-karmāṇaṁ), whose doubts have been slashed by transcendental knowledge (jñāna-sañchinna-saṁśayam) and is situated on the platform of the self (ātmavantaṁ). (BG 4.41)

Application leads to realized knowledge (jñāna) that slays doubt (sañchinna-saṁśayam). This in turn leads to absorption in the spiritual conception of life (ātmavantaṁ), as a result of which one gets freedom from the bondage to work (na karmāṇi nibadhnanti). Therefore, Krishna stresses on operating from the platform of yoga (with heart connected with Krishna) in order to slash doubts in the heart with the weapon of knowledge (jñānāsinātmanaḥ). (BG 4.42)