Karmasuklakrsnam yoginastri-vidham itaresam.
Karma = action; asukla = not white (bad); akrsnam = not black (good); Yoginah = in the case of a yogi; tri-vidham = threefold; itaresam = for others.
Karmas are neither good nor bad in the case of a yogi; they are of three types in the case of others. (IV-7).
"Desire is the case of all misery" says Buddha, the enlightened.
Desire, born due to identification with ego, motivates a person to indulge in karma, both good and bed or a mixture of the two. Indulgence in any action creates a impression that further goads one to action. So the circle of vasana-karma-vasana goes on causing birth after birth till one is fortunate enough to tread the path of yoga and free oneself from this vicious cycle.
A yogi (of high order), free from petty ego, acts not goaded by personal desires but in tune with cosmic design and, therefore, is not bound by any action good or bed. For him no action is good or bad as he transcends both the good as well as the evil.
Actions of a yogi are for Loka Sangraha, for establishing the order in the society and therefore he is untouched by them kurvannapi naiva karoti sah.
A famous episode from the life of Yogesvara Sri Krishna illustrates this point very well.
It seems once gopis of Vraja felt like going for a sort of a picnic with Sri Krishna across the river Yamuna so they prepared a variety of dishes for the purpose. But when, along with Krishna, they reached the shore, they found river in spate and, feeling helpless, approached their beloved Lord.
Krishna by that time spotted the great saga Durvasa on the bank so he advises the gopis to offer all the dishes to the ascetic and pray to him for the solution.
Durvasa happily accepts the tasty dishes all by himself and feels his hunger satisfied to the utmost. Blessing the milkmaids he directs them thus, "Tell Yamuna 'If Durvasa is nitya upavasi (ever fasting) let there be way'." Surpised at this unbelievable statement but not daring to question the saga notorious for his bad temper the gopis pray the river, "If Durvasa is nitya upavasi, let there be way for us to go across!"
And lo and behold! The river parts in two!
After gopis had all the fun across the river, they wanted to return home but river was still in flood so again they approach Krishna. This time he tells them to pray to Yamuna to give way if he was ever celibate (nitya Brahmachari). And river did part when they prayed in this manner.
Both Durvasa and Krishna were great masters, all their actions performed in the spirit of Misaim Karma (action not motivated by any personal desire). Whether they take food even breather the air to survive, it is for others, not for their own sake. For such yogis karmas are neither good nor bed and therefore create no vasana. For others they are of three types: good, bad and mixed, producing a mixed result, birth after birth.