18.9 कार्यम् ought to be done, इति thus, एव even, यत् which, कर्म action, नियतम् obligatory, क्रियते is performed, अर्जुन O Arjuna, सङ्गम् attachment, त्यक्त्वा abandoning, फलम् fruit, च and, एव even, सः that, त्यागः abandonment, सात्त्विकः Sattvic (pure), मतः is regarded.Commentary: A man of pure nature performs actions that have fallen to his lot in accordance with his capacity and his inherent nature. He is not filled with the pride that he is the performer of such actions nor does he hope for any gain therefrom.An ignorant man may think that the obligatory duties may produce their fruits for the performer by causing selfpurification and preventing the sin of omission or nonperformance. This sort of thinking and expectation of rewards also must be abandoned. Abandonment of the rewards of actions is praised in this verse.When a man does obligatory duties without agency and with unselfishness and egolessness his,mind is purified, his Antahkarana is prepared for the reception of the divine light or the dawn of Selfknowledge. He gradually becomes fit for devotion to knowledge (JnanaNishtha).The aspirant or seeker after liberation should be prepared to undergo physical sufferings. All acts of selfdiscipline and selfsacrifice entail physical suffering.This, again, is the central teaching of the Gita -- do your duty without attachment and selfish desires.