Selfishness must be transmuted into selflessness before the domain of duality is completely transcended. Persistent and continuous performance of good deeds wears out selfishness. Selfishness extended and expressed in the form of good deeds becomes the instrument of its own destruction. The good is the main link between selfishness thriving and dying.
Selfishness, which in the beginning is the father of evil tendencies, becomes through good deeds the hero of its own defeat. When the evil tendencies are completely replaced by good tendencies, selfishness is transformed into selflessness, that is, individual selfishness loses itself in universal interest. Though this selfless and good life is also bound by the opposites, goodness is a necessary step toward freedom from the opposites. Goodness is the means by which the soul annihilates its own ignorance.
-Discourses, 7th Ed, p14