To remove any doubt or misconceptions that might arise from the previous verse that sins may be crossed over but not absolved Lord Krishna gives the illustration that fire of spiritual knowledge as revealed in the Vedic scriptures burns to ashes all karmas or reactions to actions, with the exception of the prarabdha karma which was the karma by which one received their physical body.

Lord Krishna uses this illustration citing the complete eradication of all sins and their destruction to further emphasise the potency of spiritual knowledge,

One might wonder that just as crossing the ocean by boat does not destroy the ocean how is it that the boat of spiritual knowledge can destroy all one's sins. Lord Krishna states here that the boat of spiritual knowledge will destroy all reactions to actions both those leading to merit and those leading to demerit.