4.37

यथैधांसि समिद्धोऽग्निर्भस्मसात्कुरुतेऽर्जुन ।
ज्ञानाग्निः सर्वकर्माणि भस्मसात्कुरुते तथा ॥३७॥

yathaidhāḿsi samiddho 'gnir
bhasma-sāt kurute 'rjuna
jñānāgniḥ sarva-karmāṇi
bhasma-sāt kurute tathā

yathā — just as; edhāḿsi — firewood; samiddhaḥ — blazing; agniḥ — fire; bhasma- sāt — ashes; kurute — turns; arjuna — O Arjuna; jñāna- agniḥ — the fire of knowledge; sarva- karmāṇi — all reactions to material activities; bhasma- sāt — to ashes; kurute — it turns; tathā — similarly.

Text

As a blazing fire turns firewood to ashes, O Arjuna, so does the fire of knowledge burn to ashes all reactions to material activities.

Purport

Perfect knowledge of self and Superself and of their relationship is compared herein to fire. This fire not only burns up all reactions to impious activities, but also all reactions to pious activities, turning them to ashes. There are many stages of reaction: reaction in the making, reaction fructifying, reaction already achieved, and reaction a priori. But knowledge of the constitutional position of the living entity burns everything to ashes. When one is in complete knowledge, all reactions, both a priori and a posteriori, are consumed. In the Vedas (Brihad-aranyaka Upanishad 4.4.22) it is stated, ubhe uhaivaisha ete taraty amritah sadhv-asadhuni: "One overcomes both the pious and impious reactions of work."

Bhagavad Gita As It Is.

Chapter 4: Transcendental Knowledge. Text 37

As a blazing fire turns firewood to ashes, O Arjuna, so does the fire of knowledge burn to ashes all reactions to material activities.