As a well-kindled fire reduces fuel to ashes, so, oh Arjuna, the fire of knowledge reduces all actions to ashes.

The jñānāgni — fire of knowledge — does not annul past actions but burns their karmic residue (āśaya).

Samiddha — well-kindled — indicates mature knowledge, not intellectualism. Actions already performed and their potential seeds are bhasmasāt — reduced to ashes — when the discrimination between ātman and anātman is total. This is the power of jñāna-yoga.