यथैधांसि समिद्धोऽग्निर्भस्मसात्कुरुतेऽर्जुन।ज्ञानाग्निः सर्वकर्माणि भस्मसात्कुरुते तथा॥
yathaidhānsi samiddho ’gnir bhasma-sāt kurute ’rjunajñānāgniḥ sarva-karmāṇi bhasma-sāt kurute tathā
Word by word
The verse says
As a fire well lit turns firewood to ash, Arjuna, the fire of knowing turns every action to ash in the same way.
In plain words
The mechanism behind verse 36, in one image.
Samiddho agniḥ - a fire properly kindled. Not smouldering. Blazing.
And wood, which has a shape and a history and a future, becomes ash. Bhasma-sāt - reduced to ash.
Where you've felt this · in creative work
You find an old piece of work you were embarrassed by. You are not embarrassed any more, and nothing about the work has changed. It has simply stopped being something you are inside.
Going deeper
Ash is not nothing, and that is the whole point of the image.
Ash is not nothing. The wood has not been deleted; it has been transformed into something that cannot burn again. That is the exact claim being made about action: not erased, but rendered incapable of producing further consequence.
Which matches 4.19's jñānāgni-dagdha-karmāṇam, actions burnt in the fire of knowing. Burnt seed does not sprout.
Samiddha - well-kindled - is doing quiet work. A smouldering fire chars and does not consume. The image assumes a fire that has properly caught, which is why 4.34 sent Arjuna to a teacher rather than a book.
And there is an honesty in choosing fire rather than washing. Washing implies the dirt was on the surface. Fire implies the thing itself is changed and does not come back.
For a reader carrying something, the distinction is not academic. One promises you will feel better about it. The other says it will stop generating.