कर्मणो ह्यपि बोद्धव्यं बोद्धव्यं च विकर्मणः।
अकर्मणश्च बोद्धव्यं गहना कर्मणो गतिः।।4.17।।
4.17. Something has got to be understand of [good] action also; and something is to be understood of the wrong action; and something is to be understood of non-action. Difficult is to comprehend the way of action.
4.16-17 Kim karma etc. Karmanah etc. The classification of [good] action and non-action is difficult to comprehend. That is to say there is bad action even among the action that has been ordained [in the scriptures], just as the animal-slaughter in the [pious] Agnistoma sacrifice. Again, even in the midst of action, that goes against [the scripture], there is auspicious action; for example there is an end for the trouble of the people in the act of killing a murderous animal. Even in the case of non-performance of action, there do exist [both] the auspicious and inauspicious acts; for there will be necessarily [some] acts performed by the sense of speech and by the mind as they are difficult to avoid without wisdom. Therefore on account of its mysterious nature, even hte experts have not properly understood the action as : Prosperity would be for as by this [particular] auspicious action; and emancipation would be for us by that [particular] non-undertaking of [certain] actions. Therefore, it is the fire of wisdom taught in the seel, that alone is capable of positively burning down the fuel of all the auspicious and inauspicious actions; and hence that is to be sought after as a refuge. This is what is intended by the Bhagavat. In order to calrify the same, [the Lord] says -
Karmano hyapi boddhavyam boddhavyam cha vikarmanah; Akarmanashcha boddhavyam gahanaa karmano gatih.
karmaṇaḥ—recommended action; hi—certainly; api—also; boddhavyam—should be known; boddhavyam—must understand; cha—and; vikarmaṇaḥ—forbidden action; akarmaṇaḥ—inaction; cha—and; boddhavyam—must understand; gahanā—profound; karmaṇaḥ—of action; gatiḥ—the true path