ज्ञानाग्निः सर्व कर्माणि भस्मसात् कुरुते तथा ।। श्लोक ३७
As the blazing fire reduces fuel to ashes, O Arjuna, so does the fire of knowledge reduce all karma to ashes.
While in the ignorance the jivatman shares in karma in all three forms - sanchita, agamin and prarabdha. Of these three, the first remains stored up to bear fruit in the distant future and the second in the near future. The third is working itself out in the present body. The fire of knowledge destroys the first two and renders the third ineffective though operating. The jnani pays no more heed to it than he does to the shadow of his body.
The solemnity that slf knowledge brings can never be over-emphasised, as explained in the next sloka.